Ionel Drăghici

Improvement possibilities of industrial systems are driven by Industrial Internet of Things (IIoT) and Industry 4.0 concepts. The basic enablers are related to interoperation, and some efficiency and safety increasing solutions may be direct outcomes. Other benefits of interoperability are related to data integration, and the ability to analyze the collected information and to establish recipes for improvements. One of the most important targets required by the industry is the prediction capability, to forecast equipment faults or process values. The water industry with its specific characteristics is following the same path and needs efficiency increasing solutions that could be applied on its many legacy systems. Any data-driven solution is a case study driven solution. Therefore, the current research is started with deploying pilots that consists of proactive historians applied to functioning legacy water sector facilities. The work is presenting a Long-Short-Term-Memory (LSTM) neural networks-based prediction solution within the low-cost decentralized proactive historian. The exposed case study technological process is a wastewater treatment plant, where sludge pump failures are predicted to improve maintenance activities, as well as a chemical oxygen demand water quality indicator to improve process control strategy adjustments. The algorithm is generated as a result of a batch training and afterwards it is adapted also to incremental training. The solution is conceived for the hardware and software conditions of the proactive historian and the deployment within the real scenario proved excellent results, with the ability to provide 5 hours ahead correct predictions.

The industry is in continuous evolution in the context of the Industrial Internet of Things (IIoT) and Industry 4.0 requirements and expected benefits. Some sectors allow higher reconfiguration dynamics considering the interference capabilities and process/equipment renewals, but others have considerable inertia that is many times justified. In most encountered situations, the reality confirms that the industry is struggling with new demands such as interoperation and efficiency improvements. The water industry makes no difference, being a sector with critical infrastructures and highly varied subsystems, where invasive interference in legacy solutions tends to be avoided. Following previous successful footsteps in researching a proactive decentralized historian, the current work focuses on a case study that refers to a water treatment and distribution facility that has been operated for several years, and the current operating regime was established by local operators following accumulated observations, restrictions, and response strategies. The proactive historian was tailored for the current case study, and it was applied and tested in the suboptimal functioning scenario where the water sources configuration was manually selected and used for water availability and energy efficiency, but without assuming current/future failures or different water demands. The proposed low-cost historian targeted to improve the functioning and operation of the water facility considering energy efficiency and other impacting outcomes of the current strategy and to establish an automatic functioning regime in a completely non-invasive manner towards the local legacy solution. The results were satisfactory, proving that the historian is able to adapt to a particular and suboptimal functioning real industrial scenario, establish recipes in a process-aware manner, and interoperate with the local legacy solution in order to apply improving actions.

The industry is in a continuous evolution in the context of Industrial Internet of Things (IIoT) and Industry 4.0 requirements and expected benefits. Some sectors allow a higher reconfiguration dynamics considering the interference capabilities and process/equipment renewals, but others have considerable inertia that is many times justified. In most encountered situations, the reality confirms that the industry is struggling with new demands as interoperation and efficiency improvements. The water industry makes no difference, being a sector with critical infrastructures and highly varied subsystems, where invasive interference in legacy solutions tends to be avoided. Following previous successful footsteps in researching a proactive decentralized historian, the current work focuses on a case-study that refers to a water treatment and distribution facility that is operated for several years and the current operating regime was established by local operators following accumulated observations, restrictions and response strategies. The proactive historian was tailored for the current case-study and it was applied and tested in the suboptimal functioning scenario where the water sources configuration was manually selected and used for water availability and energy efficiency, but without assuming current/future failures or different water demands. The proposed low-cost historian targeted to improve the functioning and operation of the water facility considering energy efficiency and other impacting outcomes of the current strategy, and to establish an automatic functioning regime in a completely non-invasive manner towards the local legacy solution. The results were satisfactory, proving that the historian is able to adapt to a particular and suboptimal functioning real industrial scenario, to establish recipes in a process-aware manner, and to interoperate with the local legacy solution in order to apply improving actions.

Water treatment stations (WTSs) provide drinking water to the community and are critical infrastructures of any village or city. The main energy consumption of WTSs is associated with the operation of the pumping units installed in the water supply stations (WSSs). The parameters of the pumping units installed in the WSSs are continuously adjusted during service to meet the requirements of the customers. Therefore, variable-speed pumping units (VSPUs) are feasible technical solutions implemented in WSSs. Several strategies combining VSPUs and constant-speed pumping units (CSPUs) have been developed to operate in WSSs. A technical solution with four pumping units (two VSPUs and two CSPUs) is implemented in Timisoara pumping station No. 1 (TPS1) in the Bega municipal water treatment station (MWTS). The layout of TPS1 is detailed, and its energy consumption from the budget of the Bega MWTS is quantified. The operation strategy with four pumping units selected in TPS1 is investigated. The number of hours in service of each pumping unit and the total operating time of all pumping units in the last six years are examined. The specific power consumption associated with the operation of the pumping units installed in TSP1 is detailed. The failure incidents of the pumping units counted in service are enumerated and correlated with the operating conditions of the pumping units. A new strategy developed for the operation of the pumping units installed in TPS1 is proposed to better adapt to the operating conditions, improving the specific power consumption as well as diminishing the failure incidents. The new operation strategy is presented and assessed based on the data acquired from TPS1 over one year. The conclusions and the lessons learned in this case study are drawn in the last section.

This paper presents a simple to use software system for the quick assessment and monitoring of the efficiency of hydraulic generators deployed in drinking water transportation systems. The software has been validated by experimental results at constant speed and provides an easy to use smartphone application for the assessment of the efficiency using in-situ QR code stickers for the pumps in service. The estimated flow is confirmed with 3% accuracy compared against the experimental data.

The pump inlet casing deflects the fluid flow from the inlet pipe, mainly arranged normally to the axis, into the axial direction. The pump inlet casing can take a large variety of geometrical shapes from curved pipes to three-dimensional elbows. The hydrodynamic field induced by symmetrical suction elbow (SSE) at the pump inlet is experimentally investigated in order to quantify it effects at the pump inlet. The pump test rig and the experimental setup are detailed. A SSE model is installed at the pump inlet. Laser Doppler Velocimetry (LDV) measurements are performed on the annular cross section located at the pump inlet. As a result, the map of the velocity field is determined quantifying the non-uniformities induced by SSE. Next, the full 3D turbulent numerical investigation of the flow in the SSE is performed. The numerical results on the annular cross section are qualitatively and quantitatively validated against LDV data. A good agreement between numerical results and experimental data is obtained. The hydrodynamic flow structure with several pairs of vortices is identified examining the vorticity field. However, two pairs of vortices with largest contribution to the flow non-uniformity are examined. Three parameters are considered to quantify the evolution of each vortex center: two geometrical quantities (e.g. the radial and angular coordinates) and one hydrodynamic (the magnitude of vorticity). The largest values of the vorticity magnitude are identified in the center of both vortices located behind the shaft. The 3D distribution of the vortex core filaments is visualized. As a result, the 3D geometry of the SSE and the pump shaft are identified as the main sources of the flow non-uniformity at the pump inlet. This deep analysis of the 3D flow field induced by the SSE paves the way towards an improved geometry with practical applications to real pump and pump-turbines.

A strategy of urban sewage centralized management is implemented in the most cities (e.g. Timisoara). All wastewater is collected and conveyed to a central location for treatment or disposal. In the urban area, the rainwater is embedded in the wastewater management. Seven rainwater pumps are installed in a wastewater treatment plant to protect it against flooding. This type of pumps is vertically installed in Timisoara's wastewater treatment plant in order to pump the additional rainwater protecting it. Several catastrophic events have been occurred at the rainwater pumps tacking them out of service after a limited operation time. The fastening bolts of the blades are brittle broken due to the clog of the impeller with waste rag balls. The cumulated operation time is examined for each rainwater pump together with the catastrophic events identified in service. The mechanical properties of the waste fibres are experimentally determined with respect to it area in order to assess the clog/rag conditions corresponding to the clearance between the impeller blades and housing. Next, the inertial torque associated to the rotating parts of the rainwater pump is estimated to check the level when sudden locking occurs due to the impeller clogging. The maximum stress level of the fastening bolts is exceeded when the impeller is partially clogged or ragged. As a result, the root cause of the problem is associated with the ragging level of the impeller. A solution is proposed to avoid these problems.

In hydropower systems among hydropower plants there are storage pump units. In order to ensure higher flow rate, the pumps have constructive differences besides regular. Consequently, the complex shape of the suction-elbow with symmetric inlet generates an unsteady flow which is ingested by impeller. These phenomena also generate stronger unsteady flow conditions, such as stall, wakes, turbulence and pressure fluctuations, which affect the overall mechanical behaviour of the pump with vibration, noise and radial and axial forces on the rotor. Alternatively, an axial rotor can be installed in front of the impeller. In this case, the non-uniformity flow will be decreased, and the static pressure will be increased at the impeller inlet. Consequently, the efficiency behaviour practically remains unchanged while the cavitational behaviour is improved. The paper investigates experimentally a pump system with the axial rotor having variable speed, while the pump impeller has constant speed. First, the paper presents the experimental test rig, the control and acquisition system. Second, is presented the pump system equipped with the clutch in order to have variable speed for the axial rotor. Thirdly, the experimental results concentrate on the axial rotor influence on the efficiency behaviour. The last section draws the conclusions.

The purpose of this paper is to examine the failure problems encountered during the operation of the rainwater pump impellers installed in a wastewater station. The rainwater pumps are specially designed to operate in wastewater plants. The fibbers and wastes are discharged together with rainwater during storms with this type of pumps to avoid the flood of the wastewater station. Several problems have occurred in service due to the fibbers clog the gap between the impeller blades and the pump casing. The analysis of the catastrophic events associated to the rainwater pumps installed in a wastewater station is performed. As a result, it has been identified that the catastrophic events are due to the brittle fracture of the fasten bolts connecting the impeller blades and the pump hub, respectively. Analytical and numerical analysis were perform in order to determine the maximum shear stress on the fasten bolts. As a conclusion the partial clogging of the gap between one impeller blade and pump casing, inducing the lock of the blade and leading to catastrophic failure.