Luma F. Ali

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

University of Baghdad

Research Subjects

Thermodynamics

Research Interests

Luma F. Ali has a total of 9 co-authors. Here are the top co-authors by number of shared publications:

Amjad Jaleel Humaidi
College of Artificial Intelligence Engineering, University of Technology-Iraq, Baghdad 10066, Iraq
3 shared publications
Amjed A. A.
Department of Mechanical Engineering University of Baghdad Baghdad Iraq
2 shared publications
Shibly Ahmed Al-Samarraie
College of Artificial Intelligence Engineering, University of Technology-Iraq, Baghdad, Iraq
2 shared publications
Abdellatif Mohammad Sadeq
Mechanical and Industrial Engineering Department, College of Engineering, Qatar University, Doha, Qatar
1 shared publication
Amjed Abdulelah
Department of Mechanical Engineering, University of Baghdad, Baghdad 10069, Iraq ; Department of Electrical Engineering, University of Kufa, Najaf 54001, Iraq
1 shared publication
Assma S. Abdulwahed
Department of Mechanical Engineering, College of Engineering University of Baghdad Baghdad Iraq
1 shared publication

Latest Publications

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- 8 January 2026
- Published by Wiley in Heat Transfer
Numerical Analysis of Mixed Convection in Vented Curved Cavity With a Metal Foam Layer
by Luma F. Ali, Raed G. Saihood
Heat transfer applications usually contemplated day‐to‐day are primarily spotlighted on mixed convection, such as solar collector heating arrangements, electronic cooling, and drying processes. Enhancing convection heat transmission in such appliances can be achieved by inserting porous media, inflow loci, and/or line geometry. In the present paper, convection heat transmission inside a vented curved cavity () with an inserted metal foam layer ( PPI and 0.9% porosity) saturated with water was accomplished. The bottom cavity wall was discretely heated at a constant hot temperature, and the curved wall was kept at a constant cold temperature. Governing equations comprising continuity, momentum with the Darcy–Brinkmann–Forchheimer model, and local thermal equilibrium energy equation have been used and numerically resolved by utilizing the finite element scheme. The inspirations of pertinent parameters involving metal foam layer thickness (), Richardson number (, , ), Reynolds number (), inlet port position (, , ), and partial heating position (, , ) are scrutinized. The results reveal that flow and heat transfer fields are influenced chiefly by these parameter alterations. Streamlines and isotherms were affected strongly by Reynolds number and inlet port location. The average Nusselt number highly depended on the Reynolds number and the metal foam layer insertion. When and , increasing the metal foam layer thickness enlarges cavity regions with high temperature values, but when , another performance is attained. The position at is recommended in most thermal engineering applications.
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- 8 January 2026
- Published by Wiley in Heat Transfer
Numerical Analysis of Mixed Convection in Vented Curved Cavity With a Metal Foam Layer
by Luma F. Ali, Raed G. Saihood
Heat transfer applications usually contemplated day‐to‐day are primarily spotlighted on mixed convection, such as solar collector heating arrangements, electronic cooling, and drying processes. Enhancing convection heat transmission in such appliances can be achieved by inserting porous media, inflow loci, and/or line geometry. In the present paper, convection heat transmission inside a vented curved cavity () with an inserted metal foam layer ( PPI and 0.9% porosity) saturated with water was accomplished. The bottom cavity wall was discretely heated at a constant hot temperature, and the curved wall was kept at a constant cold temperature. Governing equations comprising continuity, momentum with the Darcy–Brinkmann–Forchheimer model, and local thermal equilibrium energy equation have been used and numerically resolved by utilizing the finite element scheme. The inspirations of pertinent parameters involving metal foam layer thickness (), Richardson number (, , ), Reynolds number (), inlet port position (, , ), and partial heating position (, , ) are scrutinized. The results reveal that flow and heat transfer fields are influenced chiefly by these parameter alterations. Streamlines and isotherms were affected strongly by Reynolds number and inlet port location. The average Nusselt number highly depended on the Reynolds number and the metal foam layer insertion. When and , increasing the metal foam layer thickness enlarges cavity regions with high temperature values, but when , another performance is attained. The position at is recommended in most thermal engineering applications.
Open Access
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Cited by 2
- 25 October 2025
- Published by MDPI AG in Processes
Discrete Heating and Outlet Ports’ Influences on Thermal Convection in Lid-Driven Vented Cavity System with Thermal Dispersion and LTNE Effects
by Luma F. Ali, Shibly A. Al-Samarraie, Amjad J. Humaidi
An ambit of enhancing heat transfer throughout thermal convection in a cavity is explored numerically in this study, contemplating the heat dispersal from a segmental heat source circumscribed in a square-vented porous cavity with a moving lid. The cavity can be used as a heat sink for electronic cooling, material processing, and convective drying. Aluminum $10$ PPI metal foam saturated by aluminum oxide–water nanofluid is occupied in this lid-driven vented cavity system. The bottom cavity wall is fully and partially heated by a heat source of specific length $L_{H}$ , and the left wall and inlet fluid are kept at the same cold temperature, while the right wall and top-driven wall are thermally insulated. Thermal dispersion and local thermal non-equilibrium effects are included in an energy equation, and continuity and Darcy–Brinkmann–Forchheimer momentum equations are implemented and resolved by utilizing the finite volume method with the aid of a vorticity–stream function approach operation. The inspirations behind pertinent parameters, including the Reynolds number ( $R e = 10 - 50$ ), Grashof number ( $G r = 10^{3} - 10^{6}$ ), inlet and outlet ports’ aspect ratio ( $D / H = 0.1 - 0.4$ ), outlet port location ratio ( $S / H = 0.25 - 0.75$ ), and discrete partial heating ratio ( $L_{H} / L = 0.25 - 1$ ) are scrutinized. The baseline circumstance corresponds to full-length heating $L_{H} / L = 1$ and the outlet port location ratio $S / H = 0.25$ . The results reveal that the fluid and heat flow domains are addressed mostly via these specification alterations. For $G r = 10^{3}$ , increasing $R e$ from $10$ to $40$ does not alter streamlines or the isotherm field, but when $R e = 50$ it is detected that streamlines increase monotonically. Streamlines are not altered when $L_{H} / L$ and $S / H$ are amplified but strengthened more when the opening vent aspect ratio is increased. A greater temperature difference occurs as $L_{H} / L$ is raised from $0.25 - 0.75$ and isotherms are intensified, and the thermal boundary layer becomes more distinct when $S / H$ is augmented. The average Nusselt number rises as $R e$ , $G r$ , $L_{H} / L$ , and $D / H$ are increased by about $30 %$ , $3.5 %$ , $23 %$ , and $19.4 %$ , respectively, and it decreases with $S / H$ amplifying is increased by around $5.5 %$ .
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- 25 October 2025
- Published by MDPI AG in Processes
Open Access
Discrete Heating and Outlet Ports’ Influences on Thermal Convection in Lid-Driven Vented Cavity System with Thermal Dispersion and LTNE Effects
by Luma F. Ali, Shibly A. Al-Samarraie, Amjad J. Humaidi
An ambit of enhancing heat transfer throughout thermal convection in a cavity is explored numerically in this study, contemplating the heat dispersal from a segmental heat source circumscribed in a square-vented porous cavity with a moving lid. The cavity can be used as a heat sink for electronic cooling, material processing, and convective drying. Aluminum $10$ PPI metal foam saturated by aluminum oxide–water nanofluid is occupied in this lid-driven vented cavity system. The bottom cavity wall is fully and partially heated by a heat source of specific length $L_{H}$ , and the left wall and inlet fluid are kept at the same cold temperature, while the right wall and top-driven wall are thermally insulated. Thermal dispersion and local thermal non-equilibrium effects are included in an energy equation, and continuity and Darcy–Brinkmann–Forchheimer momentum equations are implemented and resolved by utilizing the finite volume method with the aid of a vorticity–stream function approach operation. The inspirations behind pertinent parameters, including the Reynolds number ( $R e = 10 - 50$ ), Grashof number ( $G r = 10^{3} - 10^{6}$ ), inlet and outlet ports’ aspect ratio ( $D / H = 0.1 - 0.4$ ), outlet port location ratio ( $S / H = 0.25 - 0.75$ ), and discrete partial heating ratio ( $L_{H} / L = 0.25 - 1$ ) are scrutinized. The baseline circumstance corresponds to full-length heating $L_{H} / L = 1$ and the outlet port location ratio $S / H = 0.25$ . The results reveal that the fluid and heat flow domains are addressed mostly via these specification alterations. For $G r = 10^{3}$ , increasing $R e$ from $10$ to $40$ does not alter streamlines or the isotherm field, but when $R e = 50$ it is detected that streamlines increase monotonically. Streamlines are not altered when $L_{H} / L$ and $S / H$ are amplified but strengthened more when the opening vent aspect ratio is increased. A greater temperature difference occurs as $L_{H} / L$ is raised from $0.25 - 0.75$ and isotherms are intensified, and the thermal boundary layer becomes more distinct when $S / H$ is augmented. The average Nusselt number rises as $R e$ , $G r$ , $L_{H} / L$ , and $D / H$ are increased by about $30 %$ , $3.5 %$ , $23 %$ , and $19.4 %$ , respectively, and it decreases with $S / H$ amplifying is increased by around $5.5 %$ .
Cited by 2
Open Access
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Cited by 2
- 6 September 2025
- Published by MDPI AG in Computation
Effect of Heated Wall Corrugation on Thermal Performance in an L-Shaped Vented Cavity Crossed by Metal Foam Saturated with Copper–Water Nanofluid
by Luma F. Ali, Hussein Togun, Abdellatif M. Sadeq
Practical applications such as solar power energy systems, electronic cooling, and the convective drying of vented enclosures require continuous developments to enhance fluid and heat flow. Numerous studies have investigated the enhancement of heat transfer in L-formed vented cavities by inserting heat-generating components, filling the cavity with nanofluids, providing an inner rotating cylinder and a phase-change packed system, etc. Contemporary work has examined the thermal performance of L-shaped porous vented enclosures, which can be augmented by using metal foam, using nanofluids as a saturated fluid, and increasing the wall surface area by corrugating the cavity’s heating wall. These features are not discussed in published articles, and their exploration can be considered a novelty point in this work. In this study, a vented cavity was occupied by a copper metal foam with $P P I = 10$ and saturated with a copper–water nanofluid. The cavity walls were well insulated except for the left wall, which was kept at a hot isothermal temperature and was either non-corrugated or corrugated with rectangular waves. The Darcy–Brinkman–Forchheimer model and local thermal non-equilibrium models were adopted in momentum and energy-governing equations and solved numerically by utilizing commercial software. The influences of various effective parameters, including the Reynolds number ( $20 \leq R e \leq 1000$ ), the nanoparticle volume fraction ( $0 % \leq φ \leq 20 %$ ), the inflow and outflow vent aspect ratios ( $0.1 \leq D / H \leq 0.4$ ), the rectangular wave corrugation number ( $N = 5$ and $N = 10$ ), and the corrugation dimension ratio ( $C R = 1$ and $C R = 0.5$ ) were determined. The results indicate that the flow field and heat transfer were affected mainly by variations in $R e$ , $D / H$ , and $φ$ for a non-corrugated left wall; they were additionally influenced by $N$ and $C R$ when the wall was corrugated. The fluid- and solid-phase temperatures of the metal foam increased with an increase in $R e$ and $D / H$ . The fluid-phase Nusselt number near the hot left sidewall increased with an increase in $φ$ by $(25 - 60) %$ , while the solid-phase Nusselt number decreased by $(10 - 30) %$ , and these numbers rose by around $3.5$ times when the Reynolds number increased from $20$ to $1000$ . For the corrugated hot wall, the Nusselt numbers of the two metal foam phases increased with an increase in $R e$ and decreased with an increase in $D / H$ , $C R$ , or $N$ by $10 %$ , $19 %$ , and $37 %$ . The original aspect of this study is its use of a thermal, non-equilibrium, nanofluid-saturated metal foam in a corrugated L-shaped vented cavity. We aimed to investigate the thermal performance of this system in order to reinforce the viability of applying this material in thermal engineering systems.
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- 6 September 2025
- Published by MDPI AG in Computation
Open Access
Effect of Heated Wall Corrugation on Thermal Performance in an L-Shaped Vented Cavity Crossed by Metal Foam Saturated with Copper–Water Nanofluid
by Luma F. Ali, Hussein Togun, Abdellatif M. Sadeq
Practical applications such as solar power energy systems, electronic cooling, and the convective drying of vented enclosures require continuous developments to enhance fluid and heat flow. Numerous studies have investigated the enhancement of heat transfer in L-formed vented cavities by inserting heat-generating components, filling the cavity with nanofluids, providing an inner rotating cylinder and a phase-change packed system, etc. Contemporary work has examined the thermal performance of L-shaped porous vented enclosures, which can be augmented by using metal foam, using nanofluids as a saturated fluid, and increasing the wall surface area by corrugating the cavity’s heating wall. These features are not discussed in published articles, and their exploration can be considered a novelty point in this work. In this study, a vented cavity was occupied by a copper metal foam with $P P I = 10$ and saturated with a copper–water nanofluid. The cavity walls were well insulated except for the left wall, which was kept at a hot isothermal temperature and was either non-corrugated or corrugated with rectangular waves. The Darcy–Brinkman–Forchheimer model and local thermal non-equilibrium models were adopted in momentum and energy-governing equations and solved numerically by utilizing commercial software. The influences of various effective parameters, including the Reynolds number ( $20 \leq R e \leq 1000$ ), the nanoparticle volume fraction ( $0 % \leq φ \leq 20 %$ ), the inflow and outflow vent aspect ratios ( $0.1 \leq D / H \leq 0.4$ ), the rectangular wave corrugation number ( $N = 5$ and $N = 10$ ), and the corrugation dimension ratio ( $C R = 1$ and $C R = 0.5$ ) were determined. The results indicate that the flow field and heat transfer were affected mainly by variations in $R e$ , $D / H$ , and $φ$ for a non-corrugated left wall; they were additionally influenced by $N$ and $C R$ when the wall was corrugated. The fluid- and solid-phase temperatures of the metal foam increased with an increase in $R e$ and $D / H$ . The fluid-phase Nusselt number near the hot left sidewall increased with an increase in $φ$ by $(25 - 60) %$ , while the solid-phase Nusselt number decreased by $(10 - 30) %$ , and these numbers rose by around $3.5$ times when the Reynolds number increased from $20$ to $1000$ . For the corrugated hot wall, the Nusselt numbers of the two metal foam phases increased with an increase in $R e$ and decreased with an increase in $D / H$ , $C R$ , or $N$ by $10 %$ , $19 %$ , and $37 %$ . The original aspect of this study is its use of a thermal, non-equilibrium, nanofluid-saturated metal foam in a corrugated L-shaped vented cavity. We aimed to investigate the thermal performance of this system in order to reinforce the viability of applying this material in thermal engineering systems.
Cited by 2
Open Access
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Cited by 9
- 3 September 2025
- Published by MDPI AG in Energies
Performance of Double Pipe Heat Exchanger—Partially Occupied by Metal Foam—Is Better Enhanced Using Robust Adaptive Barrier Function-Based Sliding Mode Control
by Luma F. Ali, Shibly A. Al-Samarraie, Amjad J. Humaidi
Numerous thermal practical applications utilize shell and tube heat exchanger appliances to transfer heat energy between hot and cold working fluids. Incorporating metal foam to the outer periphery of inner tube improves the heat transfer process from hot water in the tube side to cold water in the shell side and consequently improves heat exchanger performance. In this study, the integration of use of a porous material together with designing a robust adaptive controller could efficiently regulate the outlet cold water temperature to the desired value. This is achieved with respect to the time required for cold water to reach the desired temperature (settling time) and the amount of hot water volume flow during a certain time span. A barrier function-based adaptive sliding mode controller (BF-based adaptive SMC) is proposed, which requires only the information of temperature measurement of cold water. The stability of BF-based adaptive SMC is proved utilizing Lyapunov function analysis. The effectiveness of proposed controller is verified via numerical results, which showed that the proposed controller could achieve considerable accuracy of cold water temperature using suitable design parameters. In addition, the robustness of controller against variation in inlet temperature is also verified. Another improvement to performance of heat exchanger system is achieved by adding the metal foam of aluminum material on inner pipe perimeter with wide range of metal foam to outer inner pipe diameters ratio ( $1 \leq s \leq 1.8$ ). The results showed that the settling time is significantly reduced which enables outlet cold water to reach the required temperature faster. With respect of the case of non-adding metal foam on inner pipe outer circumference, when $s = 1.2$ , the settling time and hot water temperature are reduced by $1 / 2$ and $17.3 %$ , respectively, while for $s = 1.8$ , they are decreased by $\leq 1 / 20$ and $35.3 %$ correspondingly. Accordingly, the required volume flow for hot water is reduced considerably.
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- 3 September 2025
- Published by MDPI AG in Energies
Open Access
Performance of Double Pipe Heat Exchanger—Partially Occupied by Metal Foam—Is Better Enhanced Using Robust Adaptive Barrier Function-Based Sliding Mode Control
by Luma F. Ali, Shibly A. Al-Samarraie, Amjad J. Humaidi
Numerous thermal practical applications utilize shell and tube heat exchanger appliances to transfer heat energy between hot and cold working fluids. Incorporating metal foam to the outer periphery of inner tube improves the heat transfer process from hot water in the tube side to cold water in the shell side and consequently improves heat exchanger performance. In this study, the integration of use of a porous material together with designing a robust adaptive controller could efficiently regulate the outlet cold water temperature to the desired value. This is achieved with respect to the time required for cold water to reach the desired temperature (settling time) and the amount of hot water volume flow during a certain time span. A barrier function-based adaptive sliding mode controller (BF-based adaptive SMC) is proposed, which requires only the information of temperature measurement of cold water. The stability of BF-based adaptive SMC is proved utilizing Lyapunov function analysis. The effectiveness of proposed controller is verified via numerical results, which showed that the proposed controller could achieve considerable accuracy of cold water temperature using suitable design parameters. In addition, the robustness of controller against variation in inlet temperature is also verified. Another improvement to performance of heat exchanger system is achieved by adding the metal foam of aluminum material on inner pipe perimeter with wide range of metal foam to outer inner pipe diameters ratio ( $1 \leq s \leq 1.8$ ). The results showed that the settling time is significantly reduced which enables outlet cold water to reach the required temperature faster. With respect of the case of non-adding metal foam on inner pipe outer circumference, when $s = 1.2$ , the settling time and hot water temperature are reduced by $1 / 2$ and $17.3 %$ , respectively, while for $s = 1.8$ , they are decreased by $\leq 1 / 20$ and $35.3 %$ correspondingly. Accordingly, the required volume flow for hot water is reduced considerably.
Cited by 9
Open Access
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Cited by 9
- 17 July 2025
- Published by MDPI AG in Processes
Offset Temperature and Amplitude–Frequency Effect on Convection Heat Transfer in Partially Gradient Porous Cavity with Different Outlet Port Locations
by Luma F. Ali, Amjad J. Humaidi
Based on admirable porous media performance and the popularity of additive manufacturing technology, gradient porous media are progressively being applied in increasing fields. In this study, convection heat transfer within a square vented cavity, partially occupied by two copper metal foam layers of $10$ and $20$ PPI saturated with nanofluid, was assessed numerically. The left wall was heated uniformly and non-uniformly by applying multi-frequency spatial heating following a sinusoidal function. Governing equations, including continuity, the Darcy–Brinkmann–Forchheimer model, and local thermal non-equilibrium energy equations, were adopted and solved by employing the finite volume method. The influences of relevant parameters, including nanoparticle concentrations $(0 % \leq φ \leq 10 %)$ , Reynolds number ( $1 \leq R e \leq 100$ ), inlet and outlet port aspect ratios $(0.1 \leq D / H \leq 0.4)$ , three outlet vent opening locations ( $(S_{o} = 0)$ left, ( $S_{o} = (H / 2 - D / 2)$ ) middle, and ( $S_{o} = (H - D)$ ) right), sinusoidal offset temperature ( $θ_{o} = 0.5$ , $1$ ), frequency ( $f = 1, 3, 5$ ), and amplitude ( $A = 0 - 1$ ), were examined. The results demonstrate that flow and heat transfer fields are impacted mainly by these parameters. Streamlines are more intensified at the upper-left corner when the outlet opening vent is shifted towards the right-corner upper wall. Fluid- and solid-phase Nusselt number increases $R e$ , $D / H$ , $θ_{o}$ , $A$ , and $f$ are raised, specifically when $A \geq 0.3$ . The Nusselt number remains constant when the frequency is raised from $3$ to $5$ , definitely when $D / H \geq 0.25$ . In uniform and non-uniform heating cases, the Nusselt number of both phases remains constant as the outlet port is shifted right for $R e \leq 10$ and slightly for higher $R e$ as the outlet vent location is translated from left to right.
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- 17 July 2025
- Published by MDPI AG in Processes
Open Access
Offset Temperature and Amplitude–Frequency Effect on Convection Heat Transfer in Partially Gradient Porous Cavity with Different Outlet Port Locations
by Luma F. Ali, Amjad J. Humaidi
Based on admirable porous media performance and the popularity of additive manufacturing technology, gradient porous media are progressively being applied in increasing fields. In this study, convection heat transfer within a square vented cavity, partially occupied by two copper metal foam layers of $10$ and $20$ PPI saturated with nanofluid, was assessed numerically. The left wall was heated uniformly and non-uniformly by applying multi-frequency spatial heating following a sinusoidal function. Governing equations, including continuity, the Darcy–Brinkmann–Forchheimer model, and local thermal non-equilibrium energy equations, were adopted and solved by employing the finite volume method. The influences of relevant parameters, including nanoparticle concentrations $(0 % \leq φ \leq 10 %)$ , Reynolds number ( $1 \leq R e \leq 100$ ), inlet and outlet port aspect ratios $(0.1 \leq D / H \leq 0.4)$ , three outlet vent opening locations ( $(S_{o} = 0)$ left, ( $S_{o} = (H / 2 - D / 2)$ ) middle, and ( $S_{o} = (H - D)$ ) right), sinusoidal offset temperature ( $θ_{o} = 0.5$ , $1$ ), frequency ( $f = 1, 3, 5$ ), and amplitude ( $A = 0 - 1$ ), were examined. The results demonstrate that flow and heat transfer fields are impacted mainly by these parameters. Streamlines are more intensified at the upper-left corner when the outlet opening vent is shifted towards the right-corner upper wall. Fluid- and solid-phase Nusselt number increases $R e$ , $D / H$ , $θ_{o}$ , $A$ , and $f$ are raised, specifically when $A \geq 0.3$ . The Nusselt number remains constant when the frequency is raised from $3$ to $5$ , definitely when $D / H \geq 0.25$ . In uniform and non-uniform heating cases, the Nusselt number of both phases remains constant as the outlet port is shifted right for $R e \leq 10$ and slightly for higher $R e$ as the outlet vent location is translated from left to right.
Cited by 9
Open Access
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- 13 May 2025
- Published by Yandy Scientific Press in Capillarity
Deviation of macro-micro tubing direct transition in liquid f low comparing to the constructal transition: Experimental study and CFD simulation
by Amjed Abdulelah, Luma F. Ali
Capillary tubes have growing domain in heat transfer applications. However, complexity of micro pumps and macro-micro constructal optimum transition section impede this growth, especially for polymeric microtubes. In this study, a simplified macro-micro transition section is proposed, analyzed and tested. Three dimensional computational fluid dynamics numerical simulation was conducted to compare between the direct simplified model and the optimal constructal model. In addition, fabrication and experimental testing of the proposed design is done to study the fluid flow behavior in such design and distribution. The numerical results of pressure fields produce comparable pressure drop outcome of the direct transition design. Further, it is notable that the drop in pressure drop increases with increasing flow rate, the fact that encourages utilizing this design for higher flow rates. Moreover, the proposed direct transition design provide a well distributed flow achieved from both the numerical results and experimental measurements. The pressure drop gradient between the central and peripheral branches is very small comparing to the pressure drop. However, this gradient increases with increasing flow rate. The flow velocity of the direct transition was comparable to that of the constructal design. The flow velocity elevation in the direct design increases with increasing flow rate. The numerical simulations consolidated by the experimental results about the fairly approximate flow velocity in the micro-branches in the direct transition design. The suggested design was applied for a liquid cooling vest system successfully and can be applied for several further micro applications. Document Type: Original article Cited as: Abdulelah, A., Ali, L. F. Deviation of macro-micro tubing direct transition in liquid flow comparing to the constructal transition: Experimental study and CFD simulation. Capillarity, 2025, 15(2): 44-52. https://doi.org/10.46690/capi.2025.05.03
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- 13 May 2025
- Published by Yandy Scientific Press in Capillarity
Open Access
Deviation of macro-micro tubing direct transition in liquid f low comparing to the constructal transition: Experimental study and CFD simulation
by Amjed Abdulelah, Luma F. Ali
Capillary tubes have growing domain in heat transfer applications. However, complexity of micro pumps and macro-micro constructal optimum transition section impede this growth, especially for polymeric microtubes. In this study, a simplified macro-micro transition section is proposed, analyzed and tested. Three dimensional computational fluid dynamics numerical simulation was conducted to compare between the direct simplified model and the optimal constructal model. In addition, fabrication and experimental testing of the proposed design is done to study the fluid flow behavior in such design and distribution. The numerical results of pressure fields produce comparable pressure drop outcome of the direct transition design. Further, it is notable that the drop in pressure drop increases with increasing flow rate, the fact that encourages utilizing this design for higher flow rates. Moreover, the proposed direct transition design provide a well distributed flow achieved from both the numerical results and experimental measurements. The pressure drop gradient between the central and peripheral branches is very small comparing to the pressure drop. However, this gradient increases with increasing flow rate. The flow velocity of the direct transition was comparable to that of the constructal design. The flow velocity elevation in the direct design increases with increasing flow rate. The numerical simulations consolidated by the experimental results about the fairly approximate flow velocity in the micro-branches in the direct transition design. The suggested design was applied for a liquid cooling vest system successfully and can be applied for several further micro applications. Document Type: Original article Cited as: Abdulelah, A., Ali, L. F. Deviation of macro-micro tubing direct transition in liquid flow comparing to the constructal transition: Experimental study and CFD simulation. Capillarity, 2025, 15(2): 44-52. https://doi.org/10.46690/capi.2025.05.03
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Cited by 1
- 30 April 2025
- Published by Wiley in Heat Transfer
A Tissue‐Stratified Anatomic Three‐Dimensional Heat Transfer Model for Evaluating Human Body Thermoregulatory Responses to Extreme Metabolic and Environmental Stressors
by Amjed A. A., Luma F. Ali
In this study, an improved three‐dimensional (3D) human thermoregulation model was developed. A stratified model of the segmented human geometry was introduced, characterizing distinct tissues and organs to activate their specific thermal responses and interactions. The main trunk geometry was modified to improve reliability and support applications, such as personal cooling systems. The model accounted for heat transport via blood arteries and emphasized changes in skin thermal conductivity to simulate vasodilation and vasoconstriction mechanisms. Additionally, the thermal effects of direct solar radiation on the human body were integrated into the mathematical framework. The model was validated using documented experimental data across various hot and cold environmental conditions and compared with recent 3D models. Results demonstrated that the enhanced model achieved better agreement with experimental data than existing unstratified segmented models. Improved stratification captured temperature variations across adjacent tissue layers, providing more accurate peripheral and core temperature distributions. A case study investigated strenuous military tasks performed under extreme heat, yielding significant medical insights. This advanced stratified anatomic model serves as a robust tool for predicting human thermoregulation during diverse activities, offering detailed core and skin temperature distributions. Furthermore, the modified sweepable geometry may enhance numerical methodologies for future 3D studies.
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- 30 April 2025
- Published by Wiley in Heat Transfer
A Tissue‐Stratified Anatomic Three‐Dimensional Heat Transfer Model for Evaluating Human Body Thermoregulatory Responses to Extreme Metabolic and Environmental Stressors
by Amjed A. A., Luma F. Ali
In this study, an improved three‐dimensional (3D) human thermoregulation model was developed. A stratified model of the segmented human geometry was introduced, characterizing distinct tissues and organs to activate their specific thermal responses and interactions. The main trunk geometry was modified to improve reliability and support applications, such as personal cooling systems. The model accounted for heat transport via blood arteries and emphasized changes in skin thermal conductivity to simulate vasodilation and vasoconstriction mechanisms. Additionally, the thermal effects of direct solar radiation on the human body were integrated into the mathematical framework. The model was validated using documented experimental data across various hot and cold environmental conditions and compared with recent 3D models. Results demonstrated that the enhanced model achieved better agreement with experimental data than existing unstratified segmented models. Improved stratification captured temperature variations across adjacent tissue layers, providing more accurate peripheral and core temperature distributions. A case study investigated strenuous military tasks performed under extreme heat, yielding significant medical insights. This advanced stratified anatomic model serves as a robust tool for predicting human thermoregulation during diverse activities, offering detailed core and skin temperature distributions. Furthermore, the modified sweepable geometry may enhance numerical methodologies for future 3D studies.
Cited by 1
Open Access
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- 24 January 2025
- Published by Wiley
A Tissue-Stratified Anatomic Three-Dimensional Heat Transfer Model for Evaluating Human body Thermoregulatory Responses to Extreme Metabolic and Environmental Stressors
by Amjed A. A., Luma Ali
In this study, an improved three-dimensional human thermoregulation model was developed. A stratified model of the segmented human geometry was introduced, characterizing distinct tissues and organs to activate their specific thermal responses and interactions. The main trunk geometry was modified to improve reliability and support applications such as personal cooling systems. The model accounted for heat transport via blood arteries and emphasized changes in skin thermal conductivity to simulate vasodilation and vasoconstriction mechanisms. Additionally, the thermal effects of direct solar radiation on the human body were integrated into the mathematical framework. The model was validated using documented experimental data across various hot and cold environmental conditions and compared with recent three-dimensional models. Results demonstrated that the enhanced model achieved better agreement with experimental data than existing unstratified segmented models. Improved stratification captured temperature variations across adjacent tissue layers, providing more accurate peripheral and core temperature distributions. A case study investigated strenuous military tasks performed under extreme heat, yielding significant medical insights. This advanced stratified anatomic model serves as a robust tool for predicting human thermoregulation during diverse activities, offering detailed core and skin temperature distributions. Furthermore, the modified sweepable geometry may enhance numerical methodologies for future three-dimensional studies.
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- 24 January 2025
- Published by Wiley
Open Access
A Tissue-Stratified Anatomic Three-Dimensional Heat Transfer Model for Evaluating Human body Thermoregulatory Responses to Extreme Metabolic and Environmental Stressors
by Amjed A. A., Luma Ali
In this study, an improved three-dimensional human thermoregulation model was developed. A stratified model of the segmented human geometry was introduced, characterizing distinct tissues and organs to activate their specific thermal responses and interactions. The main trunk geometry was modified to improve reliability and support applications such as personal cooling systems. The model accounted for heat transport via blood arteries and emphasized changes in skin thermal conductivity to simulate vasodilation and vasoconstriction mechanisms. Additionally, the thermal effects of direct solar radiation on the human body were integrated into the mathematical framework. The model was validated using documented experimental data across various hot and cold environmental conditions and compared with recent three-dimensional models. Results demonstrated that the enhanced model achieved better agreement with experimental data than existing unstratified segmented models. Improved stratification captured temperature variations across adjacent tissue layers, providing more accurate peripheral and core temperature distributions. A case study investigated strenuous military tasks performed under extreme heat, yielding significant medical insights. This advanced stratified anatomic model serves as a robust tool for predicting human thermoregulation during diverse activities, offering detailed core and skin temperature distributions. Furthermore, the modified sweepable geometry may enhance numerical methodologies for future three-dimensional studies.
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Cited by 11
- 5 October 2022
- Published by Wiley in Heat Transfer
Numerical investigation of natural convection in a square enclosure partially filled with horizontal layers of a porous medium
by Assma S. Abdulwahed, Luma F. Ali
Two‐dimensional buoyancy‐induced flow and heat transfer inside a square enclosure partially occupied by copper metallic foam subjected to a symmetric side cooling and constant heat flux bottom heating was tested numerically. Finite Element Method was employed to solve the governing partial differential equations of the flow field and the Local Thermal Equilibrium model was used for the energy equation. The system boundaries were defined as lower heated wall by constant heat flux, cooled lateral walls, and insulated top wall. The three parameters elected to conduct the study are heater length (7 ≤ ζ ≤ 20 cm), constant heat flux (150 ≤ q″ ≤ 600 W m⁻²), and porous material thickness (5 ≤ H ≤ 20 cm). The porous material used was the copper metal foam of porosity = 0.9 and pore density PPI = 10, and saturated with a fluid of Prandtl number = 0.7. On the basis of the results obtained, it was concluded that at the porous layer thickness = 5 cm, the rate of heat transferred was (74.6%) higher than when the layer height was 20 cm (the cavity is fully filled) and at the same thickness it was found that the heat rate is (51.4%) higher than when using the half filling (H = 10 cm). Further, the local and mean Nusselt number is maximum when using the largest heater size and smallest porous layer thickness. Finally, better circulation and convective modes were observed at high values of heat flux.
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Google Scholar
- 5 October 2022
- Published by Wiley in Heat Transfer
Numerical investigation of natural convection in a square enclosure partially filled with horizontal layers of a porous medium
by Assma S. Abdulwahed, Luma F. Ali
Two‐dimensional buoyancy‐induced flow and heat transfer inside a square enclosure partially occupied by copper metallic foam subjected to a symmetric side cooling and constant heat flux bottom heating was tested numerically. Finite Element Method was employed to solve the governing partial differential equations of the flow field and the Local Thermal Equilibrium model was used for the energy equation. The system boundaries were defined as lower heated wall by constant heat flux, cooled lateral walls, and insulated top wall. The three parameters elected to conduct the study are heater length (7 ≤ ζ ≤ 20 cm), constant heat flux (150 ≤ q″ ≤ 600 W m⁻²), and porous material thickness (5 ≤ H ≤ 20 cm). The porous material used was the copper metal foam of porosity = 0.9 and pore density PPI = 10, and saturated with a fluid of Prandtl number = 0.7. On the basis of the results obtained, it was concluded that at the porous layer thickness = 5 cm, the rate of heat transferred was (74.6%) higher than when the layer height was 20 cm (the cavity is fully filled) and at the same thickness it was found that the heat rate is (51.4%) higher than when using the half filling (H = 10 cm). Further, the local and mean Nusselt number is maximum when using the largest heater size and smallest porous layer thickness. Finally, better circulation and convective modes were observed at high values of heat flux.
Cited by 11
Open Access
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Cited by 3
- 20 December 2018
- Published by Al-Nahrain Journal for Engineering Sciences in Al-Nahrain Journal for Engineering Sciences
Output Feedback Adaptive Sliding Mode Control Design for a Plate Heat Exchanger
by Shibly Ahmed Al-Samarraie, Luma F. Ali
The heat exchanger is a device used to transfer heat energy between two fluids, hot and cold. In this work, an output feedback adaptive sliding mode controller is designed to control the temperature of the outlet cold water for plate heat exchanger. The discontinuous gain value of the sliding mode controller is adapted according to a certain adaptation law, where the only information required is the measurement of the outlet cold temperature. A sliding mode differentiator was design to estimate time derivative of outlet hot water temperature. Two constraints which imposed on the volumetric flow rate of the hot water (control input) were considered within the rules of the proposed adaptation law in this work. These are the control input is positive only and has a maximum value. For constructing the sliding variable, the outlet hot water temperature and its time derivative are required. The maximum allowable desired outlet cold water has been estimated as function of heat exchanger parameters and maximum control input. The simulation results demonstrate the performance of the proposed adaptive sliding mode control where the outlet cold water was forced to follow desired temperature equal to . Additionally, the robustness of the proposed controller was tested for the case where the cold inlet temperature is not constant. The results reveal the robustness of the proposed controller.
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Google Scholar
- 20 December 2018
- Published by Al-Nahrain Journal for Engineering Sciences in Al-Nahrain Journal for Engineering Sciences
Open Access
Output Feedback Adaptive Sliding Mode Control Design for a Plate Heat Exchanger
by Shibly Ahmed Al-Samarraie, Luma F. Ali
The heat exchanger is a device used to transfer heat energy between two fluids, hot and cold. In this work, an output feedback adaptive sliding mode controller is designed to control the temperature of the outlet cold water for plate heat exchanger. The discontinuous gain value of the sliding mode controller is adapted according to a certain adaptation law, where the only information required is the measurement of the outlet cold temperature. A sliding mode differentiator was design to estimate time derivative of outlet hot water temperature. Two constraints which imposed on the volumetric flow rate of the hot water (control input) were considered within the rules of the proposed adaptation law in this work. These are the control input is positive only and has a maximum value. For constructing the sliding variable, the outlet hot water temperature and its time derivative are required. The maximum allowable desired outlet cold water has been estimated as function of heat exchanger parameters and maximum control input. The simulation results demonstrate the performance of the proposed adaptive sliding mode control where the outlet cold water was forced to follow desired temperature equal to . Additionally, the robustness of the proposed controller was tested for the case where the cold inlet temperature is not constant. The results reveal the robustness of the proposed controller.
Cited by 3

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