Energy Loss Analysis of Novel Self-Priming Pump Based on the Entropy Production Theory

2019 ◽  
Vol 28 (2) ◽  
pp. 306-318 ◽  
Author(s):  
Hao Chang ◽  
Weidong Shi ◽  
Wei Li ◽  
Jianrui Liu
Keyword(s):  
Energy Loss ◽  
Entropy Production ◽  
Production Theory ◽  
Loss Analysis

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

2020 ◽  
Vol 234 (20) ◽  
pp. 4009-4023
Author(s):  
Hongyu Guan ◽  
Wei Jiang ◽  
Jianguo Yang ◽  
Yuchuan Wang ◽  
Xinghai Zhao ◽  
...  
Keyword(s):  
Energy Loss ◽  
Entropy Production ◽  
Centrifugal Pump ◽  
Optimization Design ◽  
Flow Region ◽  
Main Flow ◽  
Production Theory ◽  
Flow Rates ◽  
Loss Analysis ◽  
The Difference

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.

scholarly journals Energy Loss and Radial Force Variation Caused by Impeller Trimming in a Double-Suction Centrifugal Pump

Entropy ◽  
2021 ◽  
Vol 23 (9) ◽  
pp. 1228
Author(s):  
Qifan Deng ◽  
Ji Pei ◽  
Wenjie Wang ◽  
Bin Lin ◽  
Chenying Zhang ◽  
...  
Keyword(s):  
Energy Loss ◽  
Entropy Production ◽  
Flow Separation ◽  
Incidence Angle ◽  
High Energy ◽  
Radial Force ◽  
Production Theory ◽  
Pump Head ◽  
Radial Forces ◽  
Force Variation

Impeller trimming is an economical method for broadening the range of application of a given pump, but it can destroy operational stability and efficiency. In this study, entropy production theory was utilized to analyze the variation of energy loss caused by impeller trimming based on computational fluid dynamics. Experiments and numerical simulations were conducted to investigate the energy loss and fluid-induced radial forces. The pump’s performance seriously deteriorated after impeller trimming, especially under overload conditions. Energy loss in the volute decreased after trimming under part-load conditions but increased under overload conditions, and this phenomenon made the pump head unable to be accurately predicted by empirical equations. With the help of entropy production theory, high-energy dissipation regions were mainly located in the volute discharge diffuser under overload conditions because of the flow separation and the mixing of the main flow and the stalled fluid. The increased incidence angle at the volute’s tongue after impeller trimming resulted in more serious flow separation and higher energy loss. Furthermore, the radial forces and their fluctuation amplitudes decreased under all the investigated conditions. The horizontal components of the radial forces in all cases were much higher than the vertical components.

Optimal hydraulic design of an ultra-low specific speed centrifugal pump based on the local entropy production theory

2019 ◽  
Vol 233 (6) ◽  
pp. 715-726 ◽  
Author(s):  
Hucan Hou ◽  
Yongxue Zhang ◽  
Xin Zhou ◽  
Zhitao Zuo ◽  
Haisheng Chen
Keyword(s):  
Entropy Production ◽  
Centrifugal Pump ◽  
Orthogonal Design ◽  
High Energy ◽  
Geometrical Parameters ◽  
Production Theory ◽  
Local Entropy ◽  
Hydraulic Design ◽  
Low Specific Speed ◽  
Specific Speed

The ultra-low specific speed centrifugal pump has been widely applied in aerospace engineering, metallurgy, and other industrial fields. However, its hydraulic design lacks specialized theory and method. Moreover, the impeller and volute are designed separately without considering their coupling effect. Therefore, the optimal design is proposed in this study based on the local entropy production theory. Four geometrical parameters are selected to establish orthogonal design schemes including blade outlet setting angle, wrapping angle volute inlet width, and throat area. Subsequently, a 3D steady flow with Reynolds stress turbulent model and energy equation model is numerically conducted and the entropy production is calculated by a user-defined function code. The range analysis is made to identify the optimal scheme indicating that the combination of local entropy production and orthogonal design is feasible on pump optimization. The optimal pump is visibly improved with an increase of 1.08% in efficiency. Entropy production is decreased by 16.75% and 6.03% in impeller and volute, respectively. High energy loss areas are captured and explained in terms of helical vortex and wall friction, and the turbulent and wall entropy production are respectively reduced by 3.82% and 14.34% for the total pump.

scholarly journals Energy loss separation in NiFeMo compacts with smoothed powders according to Landgraf’s and Bertotti’s theories

2021 ◽  
Author(s):  
Denisa Olekšáková ◽  
Peter Kollár ◽  
Miloš Jakubčin ◽  
Ján Füzer ◽  
Martin Tkáč ◽  
...  
Keyword(s):  
Energy Loss ◽  
Mechanical Treatment ◽  
Positive Impact ◽  
Core Loss ◽  
Low Frequency ◽  
Treatment Method ◽  
Effective Dimension ◽  
Loss Analysis ◽  
Innovative Method ◽  
Individual Particles

AbstractThis submitted paper presents the detailed description of the energy loss separation for dc and ac low-frequency magnetic fields of NiFeMo (supermalloy) compacted powder prepared by innovative method of smoothing the surfaces of individual particles. The positive impact of mechanical treatment method on domain wall displacement is explained on the basis of Landgraf approach for dc loss analysis, and the effective dimension for eddy current in ac magnetic field is explained according to Bertotti approach for core loss analysis.

Rough Sets Based Simplified Analysis of Energy Loss Indicators in Power Plant

2011 ◽  
Vol 383-390 ◽  
pp. 4130-4133
Author(s):  
Song Feng Tian ◽  
Wei Wang ◽  
Yun Feng Tian ◽  
Shuang Bai Liu
Keyword(s):  
Power Plant ◽  
Energy Loss ◽  
Rough Sets ◽  
Power Plants ◽  
Working Condition ◽  
Thermal Power ◽  
Thermal Power Plants ◽  
Optimal Management ◽  
Loss Analysis ◽  
Key Indicators

There are many kinds of energy loss indicators in power plant, and there are some relevance among the various indicators. So extraction of the key indicators plays an important role between in energy loss analysis of power plants and optimal management of thermal power plants. Based on the characteristics of these indicators, the idea of rough sets was applied to the energy loss analysis of thermal power plants, then we proposed a new algorithm -- use fuzzy C means algorithm (FCM) to discrete cluster the energy loss indicators of thermal power plant, and then analysis simplified the results with algorithm Johnson. Real experiments (Chaozhou 1,2 and Ningde 3,4 assembling units which of the same type in the SIS system under the THA working condition)’ results had proved high accuracy and valuable of the algorithm.

Energy loss analysis of the storage tank coil heating process in a dynamic thermal environment

2021 ◽  
Vol 189 ◽  
pp. 116734
Author(s):  
Wei Sun ◽  
Qinglin Cheng ◽  
Lixin Zhao ◽  
Zhidong Li ◽  
Yang Liu
Keyword(s):  
Energy Loss ◽  
Storage Tank ◽  
Thermal Environment ◽  
Heating Process ◽  
Loss Analysis

Second Law and Energy Loss Analysis in a Turbulent Flow Through a Nozzle Type Duct

2005 ◽  
Author(s):  
S. R. Javadinejhad
Keyword(s):  
Heat Transfer ◽  
Energy Loss ◽  
Exchange Process ◽  
Dimensionless Number ◽  
Inlet Temperature ◽  
Primary Concern ◽  
Loss Analysis ◽  
Heat Exchanger Design ◽  
Heat Exchange Process ◽  
Pattern Forming

Amount of heat transfer is the primary concern in a heat exchanger design. The amount of energy that has been destroyed during the heat exchange process has been investigated by introducing a new dimensionless number. Analyises of simpler systems are often useful to understand more important features of complex pattern forming processes in various field of science and technology. The entropy generation have been studied by use of new dimensionless number . This number defined as the ratio of total energy loss to total heat transfer across the duct length. The temperature dependence on the viscosity is taken into consideration and results have been derived for various L/D ratio, nozzle angles and inlet temperature.

Influence of Guide Ring on Energy Loss in a Multistage Centrifugal Pump

2018 ◽  
Vol 141 (6) ◽  
Author(s):  
Ren Yun ◽  
Zhu Zuchao ◽  
Wu Denghao ◽  
Li Xiaojun
Keyword(s):  
Energy Loss ◽  
Entropy Production ◽  
Evaluation Method ◽  
Guide Vane ◽  
Load Flow ◽  
Hydraulic Loss ◽  
Pump Efficiency ◽  
Centrifugal Pumps ◽  
Multistage Pump ◽  
Guide Ring

Multistage centrifugal pumps are highly efficient and compact in structure. Pump efficiency can be improved by an effective understanding of hydraulic behavior and energy loss, however, the traditional hydraulic loss evaluation method does not readily reveal the specific locations of energy loss in the pump. In this study, a guide ring was imposed in multistage pumps, and an entropy production theory was applied to investigate irreversible energy loss of a multistage pump with and without guide ring. Detailed distributions of energy losses in the pumps were calculated to determine the respective entropy production rates (EPRs). The EPR values as calculated are in close accordance with actual hydraulic loss values in the pumps. EPR values were higher in the multistage pump with the guide ring than the pump without a guide ring under part-load flow conditions (0.2Qd). However, the vortex flow in the pump was weakened (or eliminated) by the guide ring as flow rate increased; this reduced energy loss in the chambers. Flow passing the chamber was stabilized by the guide ring, which decreased shock and vortex loss in the chamber and guide vane. Under both designed flow condition and overload conditions, the EPR values of the guide ring-equipped multistage pump were lower than those without the guide ring. Furthermore, minimum efficiency index (MEI) values were also calculated for the two chamber structures; it was found that overall efficiency of pump with guide ring is better than that without.

scholarly journals Numerical Investigation into the Development Performance of Gas Hydrate by Depressurization Based on Heat Transfer and Entropy Generation Analyses

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1212 ◽  
Author(s):  
Bo Li ◽  
Wen-Na Wei ◽  
Qing-Cui Wan ◽  
Kang Peng ◽  
Ling-Ling Chen
Keyword(s):  
Heat Transfer ◽  
Energy Loss ◽  
Entropy Production ◽  
Entropy Generation ◽  
Gas Hydrate ◽  
Methane Hydrate ◽  
Dynamic Properties ◽  
Entropy Production Rate ◽  
Entropy Flow ◽  
Hydrate Reservoir

The purpose of this study is to analyze the dynamic properties of gas hydrate development from a large hydrate simulator through numerical simulation. A mathematical model of heat transfer and entropy production of methane hydrate dissociation by depressurization has been established, and the change behaviors of various heat flows and entropy generations have been evaluated. Simulation results show that most of the heat supplied from outside is assimilated by methane hydrate. The energy loss caused by the fluid production is insignificant in comparison to the heat assimilation of the hydrate reservoir. The entropy generation of gas hydrate can be considered as the entropy flow from the ambient environment to the hydrate particles, and it is favorable from the perspective of efficient hydrate exploitation. On the contrary, the undesirable entropy generations of water, gas and quartz sand are induced by the irreversible heat conduction and thermal convection under notable temperature gradient in the deposit. Although lower production pressure will lead to larger entropy production of the whole system, the irreversible energy loss is always extremely limited when compared with the amount of thermal energy utilized by methane hydrate. The production pressure should be set as low as possible for the purpose of enhancing exploitation efficiency, as the entropy production rate is not sensitive to the energy recovery rate under depressurization.

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