Energy Loss In Pump Research Articles

Performance prediction and optimization of hydrogenation feed pump based on particle swarm optimization – least squares support vector regression surrogate model

Due to high power consumption and low energy efficiency of the hydrogenation feed multistage pump, conducting structural optimization design and reducing energy losses for this pump is necessary. In this study, an optimization method based on the particle swarm optimization (PSO) algorithm and least squares support vector regression (LSSVR) surrogate model is proposed. The head and efficiency are taken as the optimization objectives of the multistage pump, and the optimization design of the two impellers is carried out. Through the optimization of the surrogate model, the head and efficiency of the multistage pump are increased by 3.99% and 2.91%, respectively. It is found that the optimized impeller has more stable flow characteristics than original impeller. Further, the entropy production method is introduced to analyze the energy loss of pump. The result shows that the pump optimized by PSO-LSSVR surrogate model can reduce 9% energy consumption under nominal flow rate. It is attributed to the inhibitory effect of the optimization scheme on the horseshoe vortex at leading edge and the wake vortex at trailing edge of impeller. This study provides a new idea for the optimization design of high efficiency and low energy consumption of multistage centrifugal pumps.

Influence of Axial Matching between Inducer and Impeller on Energy Loss in High-Speed Centrifugal Pump

Studying the axial matching between the inducer and impeller is crucial for optimizing the structure of centrifugal pumps. In this paper, the SST k-ω turbulence model is used to analyze the influence of three axial positions on the internal flow and the energy loss of a centrifugal pump. Additionally, the entropy generation method is used to evaluate the energy loss in the pump. Three sets of inducer design schemes are selected based on the ratio of the distance from the trailing edge of the inducer to the impeller inlet and the impeller inlet diameter, which are λ = 0.6, λ = 0.9 (original scheme), and λ = 1.2, respectively. The results indicate that changing the axial position of the inducer between λ = 0.6 and λ = 1.2 has only a negligible effect on the overall performance of the centrifugal pump. At flow rates of 0.6Qd and 1.0Qd, the inlet pressure coefficient of λ2 is significantly lower compared to λ1 and λ3. As the flow rate increases, the pressure coefficient difference between the inlet and outlet in the inducer decreases, which leads to a more uniform streamline distribution and better development of the vortex in the flow channel. The energy loss in the inducer mainly occurs at the rim, the trailing edge, and outlet near the wall. As the flow rate increases, the entropy generation rate at the inducer rim decreases slightly and remains around 1000 W·m−3·K−1. At flow rates of 1.0Qd and 1.2Qd, the energy loss in the impeller reduces as the axial distance increases, with the exception of the flow rate 0.6Qd.

Electrolyte flow rate control for vanadium redox flow batteries using the linear parameter varying framework

In this article, an electrolyte flow rate control approach is developed for an all-vanadium redox flow battery (VRB) system based on the linear parameter varying (LPV) framework. The electrolyte flow rate is regulated to provide a trade-off between stack voltage efficiency and pumping energy losses, so as to achieve an energy efficient battery operation. The nonlinear process model is embedded in a linear parameter varying state–space description and a set of state feedback controllers are designed to handle fluctuations in current during both charging and discharging. Simulation studies have been conducted under different operating conditions to demonstrate the performance of the proposed approach. This control approach was further implemented on a laboratory scale VRB system.

Formula omitted]-plume geothermal in fluvial formations: A 2D numerical performance study using subsurface metrics and upscaling

CO2-plume geothermal (CPG) operations are considered for sufficiently permeable formations due to their superiority compared to conventional water-based geothermal systems. The fluvial heterogeneity in sedimentary reservoirs can significantly affect the pumping energy losses and heat extraction from hot sedimentary aquifers. In the present study, we have implemented the braided type of fluvial channels to account for the geological uncertainty, and investigated the subsurface performance metrics of a CPG system with a checkers-board pattern. An optimization of doublet/well spacing is performed based on the coefficient of performance (CoP), energy sweep parameter, and an objective function (f) defined specifically for optimization of the process. In addition, a sensitivity analysis on the grid resolution, braided channel thickness and orientation, and the injection flow rate and span of the supercritical (sc)-CO2 is performed. The upscaled grid resolution mainly affects the pressure-related parameters, including CoP and f, resulting in an average error of 80% and 60% between the fine- (120 × 120) and the coarse-scale (15 × 15), respectively. As a result, the grid resolution of 60 × 60 with dx≈16.5 m is found to have both acceptable average error and optimum runtime. The optimum doublet/well spacing for the present case is about L=450 m, in which the CPG system provides about 9 to 13 times higher values of f compared to cases with doublet/well spacing higher or lower than the optimum value. Moreover, injection wells with I1-I2 line parallel to channels’ orientation, provide about 30% higher f compared to the perpendicular case. However, channels’ orientation does not change the optimum doublet/well spacing (L=450 m).

A two-dimensional analytical unit cell model for redox flow battery evaluation and optimization

Cell performance optimization is important for improving the system efficiency of a redox flow battery. To gain better insights into key controlling factors of system efficiency, this work first proposed a theoretical model for a unit cell by extending a two-dimensional analytic model to a full cell. The model is then used for cell performance optimization after validating it with experimental and numerical modeling data. With the results, the activation, equilibrium, and pump energy losses are identified as the dominant battery energy losses. A guideline for reducing these sources is also proposed. Following the guideline, the mass transport coefficient is shown as a key control factor of equilibrium energy loss and Coulombic efficiency (CE). Approaches are then proposed to improve CE and system efficiency. The mass transport also controls pump rate optimization by reducing equilibrium energy loss. An optimal electrode porosity design can further improve a battery’s system efficiency based on an optimal porosity predicted by our model. The model also demonstrates distinct behaviors and overestimation in system efficiency when reduced to a zero-dimensional model. With the model, the guideline, and new insights, this work provides a reliable and efficient tool for the evaluation and optimization of redox flow batteries.

Energy consumption of an electrodialyzer desalinating aqueous polymer solutions

When performing electrodialysis (ED) to desalinate a stream, both the energy for desalination and the energy for pumping contribute to the total energy consumption, although under typical working conditions (e.g., brackish water desalination) the latter is usually negligible. However, the energy penalty might increase when desalinating viscous mixtures (i.e., viscosity of 2–20 cP). In this work, we experimentally investigate the desalination performance of an ED-unit operating with highly viscous water-polymer mixtures. The contribution of desalination and pumping energy to the total energy consumption was measured while varying diverse parameters, i.e., salinity and viscosity of the feed, and geometry and thickness of the spacer. It was found that the type of spacer did not significantly influence the energy required for desalination. The pumping energy was higher than predicted, though in most cases minimal compared to the energy for desalination. Only when using thin spacers (300 μm) and/or highly viscous feeds (12 cP), the pumping energy accounted for 50% of the total energy for low salinity feeds. Therefore, the main contributor to the energy consumption of viscous solutions is the desalination energy, provided that large spacer thicknesses (at least 450 μm) and adequate operating conditions are utilized to limit pumping energy losses.

Investigation on Energy Loss in Centrifugal Pump Based on Entropy Generation and High-Order Spectrum Analysis

Abstract Full-open, straight-blade centrifugal pumps have the advantages of simple structure and high stability at high speeds. However, this type of centrifugal pump has a large internal energy loss and low efficiency. The flow loss caused by unstable flow accounts for most of the internal energy loss of a centrifugal pump, and this energy dissipates mainly to the surroundings of the pump in the form of pressure pulsation and vibration. In this study, to effectively understand the hydraulic behavior and energy loss in a centrifugal pump, the energy losses in the pump were numerically analyzed by the entropy generation method, the distribution of the energies of pressure pulsation and vibration was evaluated based on experimental results at different flowrates, and the correlation between flow and energy loss at 20% of the design flowrate (Qd) was investigated by high-order spectrum analysis. The energies of pressure pulsation and vibration in the experiment were evaluated by the root-mean-square (RMS) value. The distribution of the entropy generation rate (EGR) indicated large energy losses at the diffusion section of the volute, clearance, tongue, and blade inlet. At 20% of the design flowrate (Qd), the energy loss was caused by the backflow near the tongue, and the EGR at EP2 had a nonlinear fundamental characteristic frequency of 0.44fn. By bispectrum and coherence analysis, the nonlinear fundamental characteristic frequencies generated by the unforced flow were analyzed, and it was found that unforced flow was transmitted to one another in the near-tongue region.

Energy loss analysis of the double-suction centrifugal pump under different flow rates based on entropy production theory

The investigation of energy loss of pump is of great significance for energy conservation and structural optimization design. And traditional methods have great limitations in researching the distribution of energy losses. In this paper, the entropy production theory is utilized to analyze the energy loss of the double-suction centrifugal pump. The numerical simulation results verified by experiments indicate that the difference in total entropy production under different flow rates is mainly affected by the entropy production in the main flow region. Moreover, the entropy production of the volute has the greatest impact on the entropy production in the main flow region, and even the proportion of entropy production in the volute at 1.2 QD operating point reaches 96%. Besides, the Q-criterion is applied to study the morphology of the vortex core in the volute. In the volute inlet region, it is found that the stable double-vortex flow has a better flow field and less energy loss than the scattered wake vortex.

Numerical and Experimental Study of a Vortex Structure and Energy Loss in a Novel Self-Priming Pump

The self-priming pump as an essential energy conversion equipment is widely used in hydropower and thermal power plants. The energy losses in the internal flow passage of the pump directly affect its work efficiency. Therefore, it is important to improve the internal flow characteristic of the pump. In the present work, a novel self-priming pump which starts without water is proposed; this pump can reduce the energy consumption as well as the time needed to start its operation. The spatial structure of the vortices in the pump is investigated by employing the Q criterion with the numerical solution of the vorticity transport equation. Based on the morphology, the vortices can be separated into three categories: Trailing Edge Vortex (TEV), Leading Edge Vortex (LEV) and Gap Leakage Vortex (GLV). Generally, the morphology of the TEV is more disorderly than that of LEV and GLV, and the intensity of TEV is significantly higher than that of the other two vortices. To determine the magnitude and distribution of energy loss in the pump, entropy production analysis is employed to study the influence of blade thickness on energy characteristics of the pump. It is found that with an increase in the flow rate, the location of energy loss transfers from the trailing edge to the leading edge of the blade, and viscous entropy production (VEP) and turbulence entropy production (TEP) are the dominant factors which influence the energy conversion in the pump. More importantly, employing the blade with a thin leading edge and a thick trailing edge can not only significantly reduce the impact of incoming flow under over-load condition (flow rate higher than the design condition) but can also increase the efficiency of the pump. Thus, an increase in thickness of the blade from the leading edge to the trailing edge is beneficial for improving the pump performance. The results of this paper can be helpful in providing guidelines for reducing the energy loss and in improving the performance of a self-priming pump.

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.

Energy and Exergy Analysis of the Condensate Pump During Internal Leakage from the Marine Steam Propulsion System

An energy and exergy analysis of the condensate pump from the marine steam propulsion system during the condensate leakage between pump stages is presented in this paper. Measurements from the steam propulsion system during exploitation were necessary for collecting all the data for the condensate pump analysis. Due to condensate leakage inside the pump casing, the producer specified condensate pressures at the pump outlet could not be obtained during the exploitation. Low condensate pressure at the pump inlet and condensate temperature slightly above the atmospheric significantly influences the pump exergy analysis. Increase in pump load resulted in an increase of pump energy and exergy losses and efficiencies. In the observed load range during the leakage, pump energy losses are between 19.88 kW and 24.78 kW, while pump energy efficiencies are between 11.12 % and 41.54 %. Pump exergy losses are slightly higher, while exergy efficiencies are slightly lower when compared to energy losses and efficiencies. During normal operation, without leakage, the pump energy efficiencies are from 5 % to 20 % higher in comparison with pump operation when the leakage occurs.

Energy and Exergy Analysis of the Condensate Pump During Internal Leakage from the Marine Steam Propulsion System

An energy and exergy analysis of the condensate pump from the marine steam propulsion system during the condensate leakage between pump stages is presented in this paper. Measurements from the steam propulsion system during exploitation were necessary for collecting all the data for the condensate pump analysis. Due to condensate leakage inside the pump casing, the producer specified condensate pressures at the pump outlet could not be obtained during the exploitation. Low condensate pressure at the pump inlet and condensate temperature slightly above the atmospheric significantly influences the pump exergy analysis. Increase in pump load resulted in an increase of pump energy and exergy losses and efficiencies. In the observed load range during the leakage, pump energy losses are between 19.88 kW and 24.78 kW, while pump energy efficiencies are between 11.12 % and 41.54 %. Pump exergy losses are slightly higher, while exergy efficiencies are slightly lower when compared to energy losses and efficiencies. During normal operation, without leakage, the pump energy efficiencies are from 5 % to 20 % higher in comparison with pump operation when the leakage occurs.

On the connectivity anisotropy in fluvial Hot Sedimentary Aquifers and its influence on geothermal doublet performance

This study finds that the geothermal doublet layout with respect to the paleo flow direction in fluvial sedimentary reservoirs could significantly affect pump energy losses. These losses can be reduced by up to 10% if a doublet well pair is oriented parallel to the paleo flow trend compared to perpendicular. The chance that flow paths are formed perpendicular to this trend strongly depends on the net sandstone volume in the reservoir. Detailed fluvial facies architecture realisations which are used in this study, are generated with a process-based approach utilizing geological data from the Lower Cretaceous Nieuwerkerk Formation in the West Netherlands Basin. Finally, this study emphasizes the importance of detailed facies architecture modelling for the assessment of both risks and production strategies in Hot Sedimentary Aquifers.

Influence of hydraulic oil viscosity on the volumetric losses in a variable capacity piston pump

The variable capacity piston pumps are elements of the great power and highest energy efficiency hydrostatic drives. They are used in the drive systems of ship equipment such as deck cranes, steering gears, main propulsion of smaller vessels. The laboratory and simulation investigations of the influence of liquid viscosity on the variable capacity displacement pump energy losses have not been so far performed. The paper presents results of the investigations of impact the hydraulic oil viscosity has on the volumetric losses in a piston pump operating in the full range of its capacity and oil pressure.

Micellar size of drag reducing cationic surfactants

Dynamic light scattering was employed to determine the effects of surfactant nature, concentration and counterion ratios, and shear on the hydrodynamic radii of micelles of commercial cationic surfactants which are powerful drag reducers in turbulent flow at high temperatures. Such surfactants are potentially useful for reducing pumping energy losses in district heating and cooling systems.

Transport of Oils as Oil-in-Water Emulsions

Turbulent flow pressure drop measurements were made for various concentrated oil-in-water emulsions which exhibit non-Newtonian behavior. The effects of oil viscosity, temperature and oil concentration on specific energy loss were evaluated. Measured turbulent friction factors consistently fell below those predicted by the Dodge and Melzner friction factor correlation, probably due to viscoelastic effects of the emulsion. Several polymer and surfactant drag reducers were tested in these emulsions, and high molecular weight polyacrylamides were found to be the most effective in further reducing pumping energy losses. The effectiveness of the polymer additives decreased with time during pump circulation.