Pumping Losses Research Articles

Adaptive neuro fuzzy selection of the most important factors for photovoltaic pumping system performance prediction

The main aim of the study was to perform a selection procedure to determine the most important factors for the photovoltaic pumping system performance prediction. As the input factors, photovoltaic modules loss, water control counter loss, pump loss and pipe system loss were used along. As the output factor performance ratio of the photovoltaic pumping system was used. The performance ratio of photovoltaic pumping system is an important parameter for quality measurement of the system. There is a need to analyze which factors have the most influence on the performance ratio in order to perform satiable calibration in order to reduce losses of the system. Adaptive neuro fuzzy inference system (ANFIS) was used to determine factors’ influence on the performance ration of the system. Root mean square error (RMSE) was used to assets the influences. Based on the RMSE values loss of photovoltaic modules has the strongest impact on the performance ratio of the system. The obtained results could be of practical usage for improving performance ration of the photovoltaic pumping system.

Direct Shape Optimization and Parametric Analysis of a Vertical Inline Pump via Multi-Objective Particle Swarm Optimization

The vertical inline pump is a single-suction single-stage centrifugal pump with a curved inlet pipe before the impeller, which usually causes a significant increase of hydraulic losses in the inline pump. Considering the matching relationship between the inlet pipe and impeller, a multi-objective direct optimization based on the MOPSO of the inlet pipe and impeller was carried out to broaden the efficient operating area of the vertical inline pump. Bezier curves were adopted to control the profiles of the inlet pipe and impeller and 39 coordinates of the control points and the blade number were selected as the optimization variables. The efficiencies of the inline pump at the part-load and nominal conditions were chosen as the objective functions, which were obtained by the automatic simulation program. A dramatic improvement in pump performance was found after optimization. In the set of Pareto solutions, the maximum increases of efficiency at part-load and nominal conditions were 8.06% and 7.33% respectively. It also reported that the inlet pipe with longer horizontal length and lower bend curvature could reduce the hydraulic losses of the inlet pipe and increase the pump performance.

Heat Transfer Amplification through Special Tube Inserts and Metallic Nanofluids in Heat Exchanger

The heat transfer amplification is highly desired in aerospace and IC engine driven vehicles. Such amplification is achieved by active and passive methods. This research focuses the passive method of a specially designed tube insert. The objective of the study is to increase the heat transfer rate in the tube side of the heat exchanger with such special insert which creates the turbulence flow. Usually water is employed as heat transfer fluid. This investigation included the suspensions of metallic particles like alumina and copper oxides to the plain water with neglected pumping loss. The alumina based nanofluid outperforms and supported well for all the considered flow cases.

Recirculation power in the balance of hydraulic losses of centrifugal pump

Recirculation power in the balance of hydraulic losses of centrifugal pump

Effect of molten salt properties on internal flow and disk friction loss of molten salt pump

Computational fluid dynamics is used to study the effect of temperature on flow structure and disk friction loss for different working fluids in a high temperature molten salt pump, which is used for concentrating solar power, the velocity profile and pressure distribution in the first stage of the pump model and the effect of the fluid property on the ring leakage, disk friction loss as well as the shear stress distribution on shroud are analyzed for the pure water and the molten salt with temperature 300?C and 565?C respectively. The main findings can be concluded as: the working fluids have little effect on pump performance and internal velocity distribution whereas the pressure of the flow field would increase with the fluid density, with the increase of the fluid viscosity, the shear stress inside the ring also increases and the total leakage can be eliminated evidently, the increase of the fluid density and viscosity show the significant responsibility for the disk friction loss, in which the fluid viscosity also increases the disk friction loss, and the viscosity is one of the most influential factors for the shroud shear stress and it can be observed that the shear stress on front shroud is higher than that on the rear shroud. It is believed that the present work can deep the understandings of the fluid structures inside the molten salt pump, which can provide some guidelines to improve the pump performance and optimize the pump structure.

Estimation of fuel efficiency of automobile and tractor diesel engines, operating with the shutdown of part of the cylinders

The analysis of previously performed studies to determine the fuel efficiency of automobile and tractor engines when a part of the cylinders is disconnected is carried out. This is done by stopping the fuel supply to them with simultaneous disconnection of the gas distribution mechanism for the same cylinders or without affecting the gas distribution organs in partial operating modes. It is shown that if the cylinder shut-off system for engines with forced ignition is used in serial engines, then additional research is required for diesels, since the results of experimental studies given in the literature are contradictory. The previously proposed methods are based on the use of experimental characteristics, empirical dependencies, and other experimental data that are valid only for specific diesels and their operating modes. In addition, the assessment of fuel efficiency is mainly performed by calculation without experimental confirmation. Therefore, the results of computational studies presented in some papers differ qualitatively from the results of experimental studies presented in other papers. A method based on generalized experimental data is proposed that allows the load characteristics of a full-size diesel engine to calculate its indicator and effective indicators when the fuel supply to some cylinders is stopped. The results of experimental and computational studies of changes in the fuel efficiency of a 4CH10,5/12 diesel engine in partial modes when a part of the cylinders is switched off are presented. At the same time, several options are considered - by stopping the fuel supply and closing the intake and exhaust valves, as well as without any impact on the organs of the gas distribution mechanism. It is shown that the improvement of the fuel economy of the 4CH10,5/12 diesel engine when a part of the cylinders is disconnected with the intake and exhaust valves closed is due to the absence of pump losses in the disconnected cylinders.

Electro-pneumatic variable valve actuation system for camless engine: Part II-fuel consumption improvement through un-throttled operation

Pumping loss during the gas exchange process becomes severe at low load operation in the conventional cam operated spark-ignition (SI) engine. In this study, the throttle body and conventional cam operated valve actuation mechanism of a single cylinder SI engine were removed. A novel in-house developed electro-pneumatic variable valve actuation system (VVA), as discussed in Part-I, was integrated and modified the conventional engine into camless engine. Air flow rates were varied using a throttle valve in the conventional engine. Whereas, for camess engine, air flow rates were varied by low intake valve lift and early intake valve closing (EIVC). It was found that the developed electro-pneumatic camless engine can inhale the same amount of air as compared to the conventional engine. The un-throttled operation in camless engine reduced the pumping loss at low engine speed and low load conditions, which helps in reducing the brake specific fuel consumption (BSFC) as compared to the conventional engine.

Modeling the effect of temperature on performance of an iron-vanadium redox flow battery with deep eutectic solvent (DES) electrolyte

Extensive models have been developed to study the performance of aqueous redox flow batteries, especially for all-vanadium flow battery. Nevertheless, there are few established models to study the non-aqueous deep eutectic solvent (DES)-based flow batteries, which have wider electrochemical window and higher energy density than do the aqueous redox flow batteries. In this study, a stationary two-dimensional model is set up to study the performance of iron-vanadium redox flow battery using DES as electrolyte, in which the property parameters of the DES are experimentally determined. The effects of temperature on the over-potentials, pump power loss, distribution of ions concentration and local current density are studied. The simulation results show that with the increase of temperature, the over-potentials decrease mildly; the electrochemical reactions inside the DES-electrolyte redox flow battery mainly happen in the area close to the membrane, which is different from the aqueous one, and the rise of temperature also leads to an improvement of electrode utilization. For the DES electrolyte with higher viscosity, the pump power loss could not be neglected. It is found that the pumping loss of the entire porous electrode largely decreases from 0.138 W at 25 °C to 0.022 W at 55 °C (with 84.05% reduction). These results are in good agreement with the experimental outcomes. Therefore, this model can be applied to predict the performance of DES based battery and further to develop new kinds of non-aqueous flow batteries.

Comparative study on the improvement of the gas exchange process efficiency of a high speed IC engine using swinging valve

Using poppet valves to control the air-fuel mixture entering and leaving the combustion chamber of an engine is just one among many other more flow efficient alternative solution. The geometry of the poppet valve and its valve seat are the main causes of the flow restriction in the internal combustion engines. The engine downsizing concept dictates to obtain more power from a given engine volume, therefore proportionally more air should be drawn into the cylinders to burn more fuel. These criteria best fulfilled with a new Swinging Valve (SwV) solution that enables the unhindered flow of air and exhaust gas through an engine’s cylinder. The filling of a cylinder is improved while the pumping losses are decreased. In this experiment, a Super Flow SF600 flow bench was used to examine a Suzuki SV650 motorcycle engine’s normal poppet valve cylinder head and a Swinging Valve cylinder head was constructed as well. First the flow parameters of the original cylinder head were obtained then the Swinging Valve head was investigated in the same way. The outcomes of the tests show the superiority of the new concept. The results will also be the base of further 0D/1D engine simulations.

Experimental Study on the Combustion and Energy Flows of Vehicle Engine Under NEDC of Cold Start

To enhance the fuel economy of a vehicle powered by a gasoline engine under road conditions, an energy flow test of a vehicle was performed experimentally under the New European Driving Cycle of cold start. The energy distributions and related influencing factors were analyzed using the test data. Results show that the effective power and thermal efficiency are mainly affected by the engine load except in the early stage of the New European Driving Cycle. Because of the retarded CA50 and longer CA10-90, the effective thermal efficiency is lower in the early phase of driving conditions. Initially, the heat transfer loss mainly comprises the loss of the heating, ventilation, and air conditioning system. The radiator then plays the major role, with its percentage affected by the engine load and decreasing under the extra-urban driving cycle. The exhaust gas loss is decided by the temperature and flow rate of the exhaust gas, while its percentage is mainly affected by the temperature of the exhaust gas. In the early phase of driving conditions, the retarded spark advance angle leads to a higher temperature of the exhaust gas and a greater exhaust gas loss. The pumping loss and its percentage are mainly determined by the engine speed under the urban driving cycle, and both decrease under the extra-urban driving cycle except at maximum vehicle speed.

Effect of a novel mechanical CVVL system on economic performance of a turbocharged spark-ignition engine fuelled with gasoline and ethanol blend

In order to improve the fuel economic performance of the gasoline engine, a novel mechanical continuously variable valve lift (CVVL) system with self-regulation of the valve timing (CVVLT) is proposed. The bench tests are conducted on the original and prototype engines with the ethanol blend fuel. Then, a simulation model is developed to evaluate the benefits of the proposed CVVLT system. Moreover, theoretical analysis of intake pumping losses in two engines is carried out, and the comparison between the CVVLT engine and original engine is performed in this regard. According to tested dates, it is found that on the one hand, compared with the original engine, the PMEP of the CVVLT engine at 1500 r/min, 2000 r/min and 3000 r/min are decreased by 23%, 25% and 22%, respectively. On the other hand, the improvements in the fuel economy at 2000 r/min and 3000 r/min reach 14% and 11%, respectively at low to medium load conditions. Although the EVVLT system slightly lengthens the combustion process at low loads, it greatly improves the gross mechanical efficiency and thus improves the effective thermal efficiency. Simulation results show that the retarded intake valve opening timing positively affects the combustion quality and the optimized valve opening timing can reduce the fuel consumption up to 1%–2%. The results demonstrate the proposed CVVLT system has a high potential for improving the economic performance of conventional spark-ignition engines in the low to medium load conditions.

Experimental and CFD Investigation on Flow Behaviors of a NPP Pump under Natural Circulation Condition

Passive safety system is the core feature of advanced nuclear power plant (NPP). It is a research hotspot to fulfill the function of passive safety system by improving the NPP natural circulation capacity. Considering that the flow behaviors of stopped pump pose a significant effect on natural circulation, both experimental and computational fluid dynamics (CFD) methods were performed to investigate the flow behaviors of a NPP centrifugal pump under natural circulation condition with a low flow rate. Since the pump structure may lead to different flows depending on the flow direction, an experimental loop was set up to measure the pressure drop and loss coefficient of the stopped pump for different flow directions. The experimental results show that the pressure drop of reverse direction is significantly greater than that of forward direction in same Reynolds number. In addition, the loss coefficient changes slightly while the Reynolds number is greater than 8 × 104; however, the coefficients show rapid increase with the decrease in Reynolds number under lower Reynolds number condition. According to the experimental data, an empirical correlation of the pump loss coefficient is obtained. A CFD analysis was also performed to simulate the experiment. The simulation provides a good accuracy with the experimental results. Furthermore, the internal flow field distributions are obtained. It is observed that the interface regions of main components in pump contribute to the most pressure losses. Significant differences are also observed in the flow field between forward and reverse condition. It is noted that the local flows vary with different Reynolds numbers. The study shows that the experimental and CFD methods are beneficial to enhance the understanding of pump internal flow behaviors.

Study of an innovative three-pole igniter to improve efficiency and stability of gasoline combustion under charge dilution conditions

A diluted cylinder charge helps in engine fuel efficiency but at the same time presents significant challenges to combustion stability. An innovative three-pole spark igniter is researched to explore multi-spot ignition technology and improve the burning process of high-efficiency combustion under diluted conditions. The unique design features three independent pairs of electrodes in a single spark plug and allows new approaches to apply novel ignition strategies. Optical combustion vessels and high-speed imaging techniques are employed to develop fundamental understandings of the multi-spot ignition process. A large number of tests are performed on instrumented combustion vessels to statistically quantify and demonstrate the effect of the three-pole igniter, in comparison with a conventional spark plug. Finally, the prototype three-pole igniter is implemented on a production engine to validate and demonstrate the improvements in engine combustion under low and high dilution conditions. As shown by test results, the three-pole igniter offers shorter ignition delay and faster burning, thereby improving combustion phasing and fuel economy. The three-pole igniter exhibits greater advantages for combustion stability under high dilution conditions that reduce pumping loss and thus gains fuel economy.

Attenuated cardiac function degradation in ex vivo pig hearts.

Isolated hearts offer the opportunity to evaluate heart function, treatments, and diagnostic tools without in vivo factor interference. However, the early loss of cardiac function and edema occur over time and do limit the duration of the experiment. This research focuses on delaying these limitations using optimal blood control. This study examines whether blood conditioning by means of the combination of blood predilution and hemodialysis can significantly reduce cardiac function degradation. Slaughterhouse porcine hearts were revived in the PhysioHeart™ platform to restore physiological cardiac performance. Twelve hearts were divided into a control group and a dialysis group; in the latter group, hemodialysis was attached to the blood reservoir. Cardiac hemodynamics and blood parameters were recorded and evaluated. Blood conditioning significantly reduced the loss of cardiac pump function (control group vs dialysis group, -14.9 ± 6.3%/h vs -9.7 ± 2.7%/h) and loss of cardiac output (control group vs dialysis group, -11.8 ± 3.4%/h vs -5.9 ± 2.0%/h). Hemodialysis resulted in physiological and stable blood parameters, whereas in the control group ions reached pathological values, while interstitial edema still occurred. The combination of blood predilution and hemodialysis significantly attenuated ex vivo cardiac function degradation and delayed the loss of cardiac hemodynamics. We hypothesized that besides electrolyte and metabolic control, the hemodialysis-accompanied increase in hematocrit resulted in improved oxygen transport. This could have temporarily compensated the deleterious effect of an increased oxygen-diffusion distance due to edema in the dialysis group and resulted in less progression of cell decay. Clinically validated measures delaying edema might improve the effectiveness of the PhysioHeart™ platform.

Heat transfer and fluid flow characteristics of tubular channel partially filled with grooved metal foams

The metal foam is a type of porous media that can be characterized by high porosity, tortuous flow paths, high strength to weight ratio and high thermal conductivity. Due to these features the metal foam is used in many engineering applications such as heat exchanges. Therefore, a new design of a circular pipe partially filled with a grooved metallic foam is proposed in order to improve the hydraulic and thermal performance, and consequently reduce the pumping power losses and the metal foam volume.In the current work, the non-Darcy laminar forced convection flow is considered under the thermal boundary condition of constant wall heat flux. The governing equations are solved using the finite volume method (FVM) with temperature-dependent water properties. The variable parameters are; the pitch of the helical grooves, the number of helical grooves and the aspect ratio (Ri: diameter ratio of the metal foam to the pipe). The results show that for Ri = 0.55, four helical grooves having two pitches provides the optimal increase in the Nu number (7%) and the PEC is around 1.21 with a reduction in the pumping power and the amount of the metal foam about 25% and 16.74%, respectively, at Re = 1000.

Flow batteries for energy management: Novel algebraic modelling approaches to properly assess their value

Abstract Redox Flow Battery (RFB) systems are promising technologies for the multi-hour electrical energy storage that will be necessary for on-demand electricity supply based on wind and solar power. Deriving maximum value from a RFB requires optimisation of both the system design and its operation. In this work three novel algebraic modelling approaches are introduced to represent RFB operation more accurately while maintaining quick optimisation times. First the typical linear programming (LP) optimisation problem is re-posed in terms of current-density rather than power, allowing voltaic losses to be expressed as a quadratic function (QP). Secondly, it is then shown that the current-density framework supports a novel constraint for the avoidance of high cell voltage that may damage the stack. Thirdly, for the first time a binary variable (MIQP) to describe active/idle states is introduced. This allows coulombic leakage and pumping losses to be modelled as fixed terms without constantly draining the RFB, and it allows for the optimisation of pump rating in a VRFB. In a day-ahead energy management case study, it is found that the QP optimisation predicts an additional 19% annual revenue when compared to the LP optimisation. This capture of the true flexibility of the RFB operation allows its full value to be assessed, and therefore advances the case for their deployment within the energy system. Furthermore, the formulations developed are not only applicable to RFBs but to the scheduling of other battery systems, particularly Li–ion, and balance of plant optimisation, such as the sizing of inverters and climate control systems in the context of parasitic losses.

Influence of blade profile on energy loss of sewage self-priming pump

Sewage self-priming pumps are widely used in municipal sewage treatment and agricultural irrigation. The impeller is the key component to determine the hydraulic performance of sewage self-priming pump. In this study, the ZW100-100-15 sewage self-priming pump was selected as a research object. Five double-channel impellers with different blade profiles were designed based on the same meridional shape. The ANSYS CFX 16.2 and shear stress transport k–ω turbulence model were conducted to investigate the sewage pump models with five different impellers numerically. The entropy production theory was applied to analyze the internal energy losses of different sewage pump models. The mechanism of influence of blade profiles on the energy losses was investigated systematically. The results indicated that under different flow rate conditions, the hydraulic efficiency of S5 scheme with a concave blade angle distribution profile is higher than that of other schemes. At the design flow rate, the head of S5 was the highest, the flow state inside the impeller was the most stable and the energy loss inside the impeller was the least. In non-design conditions, the flow distribution and entropy production rate distribution of S5 were significantly better than those of other schemes. Results illustrated that flow separation, backflow, shock effect, vortex and rotor–stator interaction were the main inducers for the formation of entropy production. This research indicated that the entropy production theory can predict the irreversible energy loss in pump accurately and the blade profile optimization can effectively improve the sewage self-priming pump hydraulic performance and weaken the unstable flow and its internal energy loss.

Analysis of charge exchange in a single-cylinder of spark ignition engine

The article presents the results of tests carried out on a single-cylinder of spark-ignition engine. The charge exchange process in the combustion chamber is very important to determine the possibility of improving the overall efficiency of the engine. Describes of impact modifications engine on open indicator diagrams. Open indicator diagrams show that the higher compression ratio is assumed, the higher the pressure in the system is. First parts of the research describes analysis of charge exchange on not working engine. Results of research presents different open indicators diagrams. Then the pressure results were obtained on the working engine. The possibilities of improving the overall efficiency of the engine by reducing the pumping loss, associated with the replacement of the air fuel mixture, were presented. The article describes the modification of a spark-ignition engine that affects the pressure change in the combustion chamber. The use of innovative methods of regulating the compression pressure gives a lot of positive effects.

Cross-Coupled Charge Pump Synthesis Based on Full Transistor-Level

This paper presents utility for the design of the cross-coupled charge pump, which is used for supplying peripherals with low current consumption on the chip, as the EEPROM or FLASH memories. The article summarizes the knowledge in the field of the theoretical and practical analysis of the cross-coupled charge pump (design relationships and their connection with the pump parameters, as the threshold voltage, power supply voltage, clock signal frequency, etc.) that are applicated in the design algorithm. Optimal MOSFETs sizes (W, L) were find based on the construct of the time response characteristics of the pump sub-block and finding of the maximal voltage increase in the active interval of the clock signal and minimizing of the pump losses, as the switch reverse current, inverter cross current, etc. Synthesis process includes the design of the pump functional blocks with dominant real properties, which are described based on BSIM equations for long channel MOSFET. The pump stage complex model is applicated for estimation of the number of pump stages via state-space model description and using of the interpolation polynomial functions in the algorithm. It involves the construction of the time response characteristic due to the state variables and prediction of the number of the pump stages for the next cycle based on the previous data. Optimization of the pump area is based on the minimizing of the main capacitor in each of the pump stages (number of the pump stages must be increased to obtain the desired output voltage value.) Access is designed to stress the maximum pump voltage efficiency. The whole procedure is summarized in the practical example, in which the solution is shown both in terms of maximal voltage efficiency and the optimal pump area on a chip with respect to the clock signal frequency. Added functions of the design environment are explained, inclusive of the designed pump netlist generating for professional design environment Mentor Graphics including the real models of components that are available in library MGC Design Kit. The procedure gives designer credible results without long timeconsuming optimization process. In addition, the complex model allows the inclusion effects of higher-levels.

Experimental investigation of the effects of CR, hydrogen addition strategies on performance, energy and exergy characteristics of a heavy-duty NGSI engine fueled with 99% methane content

In order to analyze and improve thermodynamic process of NGSI engine and achieve better energy utilization, a low CR (11.6) SI engine was modified by replacing pistons with different bowl volumes and an experimental investigation of the effects of CR (13.6 and 14.5), hydrogen addition strategies on performance, energy and exergy characteristics of a heavy-duty NGSI engine fueled with 99% methane content was conducted. The results showed that the PCP, maximum HRR and in-cylinder temperature increased obviously with the increase of hydrogen contents, CR and engine speed, and the locations of PCP and maximum HRR advanced towards TDC, which led to the advance of 50% combustion position, shorter combustion duration and more output work. Secondly, with the increase of hydrogen contents and CR, the proportions of indicated work and heat transfer energy to coolant turned larger but the unaccounted losses and combustion loss became smaller. In addition, with the increase of engine speed, both indicated work and friction loss were large, which caused the decrease of BTE, besides, the percentage of friction loss and pumping loss turned up. And the hydrogen contents and CR had little effect on exhaust energy and exergy. Finally, comparing the energy and exergy of NGSI engine under operated conditions, the change trends of exergy terms were similar to their corresponding energy, however, the exergy efficiency was 7.97–9.70% lower than BTE and the percentage of exhaust energy and heat transfer energy to coolant was 2.46–2.51 and 7.09–8.09 times larger than corresponding energy, respectively.