scholarly journals Dynamic simulation of inner flow in a photovoltaic pump based on Simulink and CFD

2021 ◽  
Author(s):  
Xianfang Wu ◽  
Heyu Ye ◽  
Minggao Tan ◽  
Houlin Liu
Keyword(s):  
Solar Radiation ◽  
Pressure Pulsation ◽  
Transient Flow ◽  
Guide Vane ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Maximum Error ◽  
Pump System ◽  
Impeller Outlet ◽  
Pump Flow Rate

Abstract To study the internal flow characteristics of the photovoltaic pump under the transient change of the solar radiation, the simulation algorithm of the photovoltaic pump system was established by MATLAB/Simulink and CFD for the first time and the results were validated by the test. Firstly, the change rule of pump flow rate and rotation speed under transient solar radiation was obtained by Simulink. Then the results of the change rule were transformed into the boundary condition of CFD by CEL function and the transient flow field in the photovoltaic pump was obtained. The internal flow characteristics and pressure pulsation in the pump were analyzed when the solar radiation increases or decreases transiently. The results demonstrate that the numerical calculation can provide accurate prediction for the characteristics of internal flow in the pump. The numerical results are closed to experimental results, the minimum error of pressure is 0.93% and the maximum error is 1.78%. When the solar radiation increases transiently, the low pressure area at the impeller inlet gets larger obviously and the jet-wake at the impeller outlet becomes more obvious. The pressure pulsation in impeller gradually increases and becomes stable after 0.6 s. The pressure from the impeller outlet to guide vane outlet is stable at 123 kPa. When the solar radiation decreases transiently, the pressure in the impeller takes 1.6 s to be stable. Larger pressure pulsation occurs from the impeller outlet to the guide vane inlet and the maximum differential pressure is 10 kPa. Compared with the transient increase of solar radiation, the pressure in the impeller takes more 0.2 s to stabilize when the solar radiation transient decreases. Meanwhile, the results in this paper can provide references for other transient characteristics research.

scholarly journals Numerical and Experimental Investigation of External Characteristics and Pressure Fluctuation of a Submersible Tubular Pumping System

Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 949 ◽  
Author(s):  
Yan Jin ◽  
Xiaoke He ◽  
Ye Zhang ◽  
Shanshan Zhou ◽  
Hongcheng Chen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Pressure Fluctuation ◽  
High Efficiency ◽  
Pressure Pulsation ◽  
Guide Vane ◽  
Measurement Data ◽  
Flow Characteristics ◽  
Measuring Point ◽  
Pumping System ◽  
Impeller Outlet

This paper presents an investigation of external flow characteristics and pressure fluctuation of a submersible tubular pumping system by using a combination of numerical simulation and experimental methods. The steady numerical simulation is used to predicted the hydraulic performance of the pumping system, and the unsteady calculation is adopted to simulate the pressure fluctuation in different components of a submersible tubular pumping system. A test bench for a model test and pressure pulsation measurement is built to validate the numerical simulation. The results show that the performance curves of the calculation and experiment are in agreement with each other, especially in the high efficiency area, and the deviation is minor under small discharge and large discharge conditions. The pressure pulsation distributions of different flow components, such as the impeller outlet, middle of the guide vane, and guide vane outlet and bulb unit, are basically the same as the measurement data. For the monitoring points on the impeller and the wall of the guide vane especially, the main frequency and its amplitude matching degree are higher, while the pressure pulsation values on the wall of the bulb unit are quite different. The blade passing frequency and its multiples are important parameters for analysis of pressure pulsation; the strongest pressure fluctuation intensity appears in the impeller outlet, which is mainly caused by the rotor–stator interaction. The farther the measuring point from the impeller, the less the pressure pulsation is affected by the blade frequency. The frequency amplitudes decrease from the impeller exit to the bulb unit.

scholarly journals Analysis of Internal Flow Characteristics of a Startup Pump Turbine at the Lowest Head under No-Load Conditions

2021 ◽  
Vol 9 (12) ◽  
pp. 1360
Author(s):  
Wei Wang ◽  
Xi Wang ◽  
Zhengwei Wang ◽  
Mabing Ni ◽  
Chunan Yang
Keyword(s):  
High Speed ◽  
Pressure Pulsation ◽  
Working Condition ◽  
Guide Vane ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Operating Conditions ◽  
Small Range ◽  
Pressure Balance ◽  
Pump Turbine

The instability of the no-load working condition of the pump turbine directly affects the grid connection of the unit, and will cause vibration and damage to the components of the unit in severe cases. In this paper, a three-dimensional full flow numerical model including the runner gap and the pressure-balance pipe was established. The method SST k-ω model was used to predict the internal flow characteristics of the pump turbine. The pressure pulsation of the runner under different operating conditions during the no-load process was compared. Because the rotation speed, flow rate, and guide vane opening of the unit change in a small range during the no-load process, the pressure pulsation characteristics of the runner are basically the same. Therefore, a working condition was selected to analyze the transient characteristics of the flow field, and it was found that there was a high-speed ring in the vaneless zone, and a stable channel vortex was generated in the runner flow passage. Analyzing the axial water thrust of each part of the runner, it was found that the axial water thrust of the runner gap was much larger than the axial water thrust of the runner blades, and it changed with time periodically. It was affected by rotor stator interaction. The main frequency was expressed as a multiple of the number of guide vanes, that is, vanes passing frequency, 22fn. During the entire no-load process, the axial water thrust of the runner changed slowly with time and fluctuated slightly.

Influence of non-uniform inflow on unsteady internal flow characteristics of waterjet pump

2021 ◽  
Author(s):  
Chao Liu ◽  
Hongxun Chen ◽  
Zheng Ma
Keyword(s):  
High Speed ◽  
Pressure Pulsation ◽  
Guide Vane ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Energy Performance ◽  
Hydrodynamic Characteristics ◽  
Area Formula ◽  
Low Speed ◽  
Waterjet Pump

Waterjet propulsion has many advantages when operating at high-speed conditions. As a special way of navigation, it is mostly used in high-speed ships and shallow draft ships. In this paper, a mixed-flow waterjet pump was taken as the research object. For the two cases of non-uniform inflow and uniform inflow, a modified RANS/LES method was adopted for unsteady calculation of the whole channel, aiming at investigating the influence mechanism of the non-uniform inflow on the energy performance and pressure pulsation characteristics of the waterjet pump. The hydrodynamic characteristics of the waterjet pump were comprehensively analyzed such as head, efficiency, axial-force, internal flow and pressure pulsation. It is found that the non-uniform inflow will reduce the external characteristics of the waterjet pump and lead to the huge fluctuation of energy performance with time. Low-speed swirls occur locally in the intake duct for non-uniform inflow, in which condition the vorticity is much higher than that for uniform inflow. In terms of the low-speed area, [Formula: see text] and [Formula: see text], the values under non-uniform inflow condition are generally larger than those under uniform flow condition when in the impeller and guide vane zone. The dominant frequencies of pressure pulsation are, respectively, [Formula: see text], 7[Formula: see text] and 4[Formula: see text] in the intake duct, impeller and diffuser, which are almost consitent for the two cases. However, the frequency features are more diverse, and the amplitudes corresponding to the same frequencies are more intense for non-uniform inflow.

Numerical Simulation of Transient Flow Inside Nozzle on Gasoline Direct Injection Engine

2012 ◽  
Vol 466-467 ◽  
pp. 1237-1241
Author(s):  
Yan Hua Wang ◽  
Shi Chun Yang ◽  
Yun Qing Li
Keyword(s):  
Kinetic Energy ◽  
Transient Flow ◽  
Direct Injection ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Turbulence Kinetic Energy ◽  
Gasoline Direct Injection ◽  
Injection Hole ◽  
Gasoline Direct Injection Engine ◽  
Nozzle Configuration

To achieve transient flow characteristics at exit of nozzle orifice on gasoline direct injection engine, two phase Euler-Euler schemes was used to simulate the internal flow of the swirl nozzle. Different flow characteristics were calculated in the simulation. Different kinds of nozzle configuration were studied. Cavitaion and swirl flow occured in the nozzles. Injection hole configuration matters more than area variation of swirl tangential slot to discharge coefficient of the studied nozzle. Discharge coefficient changes a little along the injection hole length. The area of the swirl tangrntial slot plays an important throttling action in nozzle internal flow. Smaller area of swirl tangential slot generates larger degree cavitation but smaller mean injection velocity. Turbulence kinetic energy changes with the time of cavitation and swirl field occurring and the nozzle configuration. Before the appearance of cavitation, smaller inclination angle of orifice can generate more turbulence kinetic energy. After that moment, turbulence kinetic energy varies with different configuration. Along injection hole length, turbulence kinetic energy obviously varies. These flow characteristics affect primary atomization and will be as input for next spray simulation. They are also applied to design reference for injection nozzle.

Study on pressure pulsation characteristics of reactor coolant pump during the idling transition process

2019 ◽  
Vol 25 (18) ◽  
pp. 2509-2522 ◽  
Author(s):  
Xiuli Wang ◽  
Yonggang Lu ◽  
Rongsheng Zhu ◽  
Yuanyuan Zhao ◽  
Qiang Fu
Keyword(s):  
Pressure Pulsation ◽  
Transient Flow ◽  
Guide Vane ◽  
Transition Process ◽  
Dynamics Simulation ◽  
Discrete Wavelet ◽  
Flow Process ◽  
Coolant Pump ◽  
Rotating Speed ◽  
Reactor Coolant

The idling characteristic of the reactor coolant pump is one of the important indicators for the safe operation of the nuclear power system. The idling transition process of the reactor coolant pump under the power failure accident condition belongs to the transient flow process. During most of the time of the idling transition process, the parameters of flow, rotating speed, and head are all nonlinear changes, and the study of the idling change law is extremely difficult. This paper introduces the nonlinear inertia transient phase of the reactor coolant pump and the principle of wavelet analysis. Based on the experimental results of the idling transition process, the polynomial fitting of the flow curve and the rotating speed curve is fitted, and the idling transient equation is established which is a boundary condition for computational fluid dynamics simulation of the nonlinear idling transient stage of the reactor coolant pump with different types of guide vanes. The signal fluctuation of pressure pulsation time-domain change at the volute outlet in different sub-bands is analyzed by means of a fast, discrete wavelet transform, and the effects of different vane optimizations in different idling stages are analyzed. It was found that the pressure fluctuation amplitude of each sub-frequency range of pump outlet in the model of the shunt guide vane is significantly smaller than that of the normal guide vane.

An Experimental Study of Rotor-Filter Pump Performance

1982 ◽  
Vol 104 (3) ◽  
pp. 259-268
Author(s):  
K. M. Marshek ◽  
M. R. Naji ◽  
G. C. Andries
Keyword(s):  
Pressure Pulsation ◽  
Flow Characteristics ◽  
Hydraulic Pressure ◽  
Motor Speed ◽  
Rotor Vibration ◽  
Pump Frequency ◽  
Pump System ◽  
Pump Performance ◽  
Filter Pump ◽  
Pulsing Flow

The performance of a rotor-filter pump has been studied experimentally. To develop an understanding of pump performance, and in particular to discern the mechanism of hydraulic pulsing, flow visualization in the rotor, vibration analyses of the pump, frequency analysis of the pump hydraulic pressure pulsation, and analyses of flow characteristics for different pick-up tubes in combination with different impellers and cover plates were conducted. The frequencies of the pump’s hydraulic pulsation is shown to be a function of the number of pick-up arms and the motor speed. The pump vibration and its pulsation amplitude were reduced by increasing the number of pick-up arms or by adding a radial impeller. These actions increased the lowest frequency of pulsation and decreased the chance of excitation of the pump system parts.

A Study on Improvement of Aerodynamic Performance for 100HP Axial Fan Blade and Guide Vane Using Response Surface Method

2019 ◽  
Author(s):  
Young-Seok Choi ◽  
Yong-In Kim ◽  
Sung Kim ◽  
Seul-Gi Lee ◽  
Hyeon-Mo Yang ◽  
...  
Keyword(s):  
Objective Function ◽  
Response Surface ◽  
Response Surface Method ◽  
Guide Vane ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Aerodynamic Performance ◽  
Axial Fan ◽  
Surface Method

Abstract This paper describes the numerical optimization of an axial fan focused on the blade and guide vane (GV). For numerical analysis, three-dimensional (3D) steady-state Reynolds-averaged Navier-Stokes (RANS) equations with the shear stress transport (SST) turbulence model are discretized by the finite volume method (FVM). The objective function is enhancement of aerodynamic performance with specified total pressure. To select the design variables which have main effect to the objective function, 2k factorial design is employed as a method for design of experiment (DOE). In addition, response surface method (RSM) based on the central composite design applied to carry out the single-objective optimization. Effects on the components such as bell mouth and hub cap are considered with previous analysis. The internal flow characteristics between base and optimized model are analyzed and discussed.

Coupled Fluid-Thermal-Solid Simulation of Axial Through-Flow Rotating Cavities

2013 ◽  
Author(s):  
Wei-lin Yi ◽  
Xiao-hang Zhang ◽  
Lu-cheng Ji ◽  
Jiang Chen
Keyword(s):  
Simulation Model ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Internal Flow ◽  
Maximum Error ◽  
Thermal Simulation ◽  
Transfer Model ◽  
Rotating Cavity ◽  
Aero Engine ◽  
Secondary Air

The rotating cavities of aero-engine compressors are the main part of secondary air flow system. It is known that there are typical multidisciplinary fluid-thermal-solid coupling characteristics in them. The high precision prediction of disc surface temperature is very important for structure designer to select materials, control blade clearances et al. The aim of this paper is to investigate the aerodynamic-thermal simulation model to obtain the method and tool for reliable temperature prediction. The paper firstly selected publicly available experimental data of two rotating cavity geometries with twin-discs to validate the precision of established fluid-thermal simulation model with the different grids, difference schemes and turbulence models. The results showed that the RNG-KE turbulence model with QUICK scheme has the better simulation precision for flow structure and Nusselt number distribution. Based on the above research, a fluid-thermal-solid coupling simulation of a twin-cavities model which is approaching to the real conditions of aero-engine has been carried out. The wall temperature distribution on inner surface has been obtained and its maximum error comparing with the experimental value is 8°C. Also the results further validated the reliabilities of the flow model, heat transfer model and fluid-thermal-solid coupling model. The paper also shows the flow field structure of rotating cavity for further understanding the internal flow characteristics.

Study and Investigation on the Mach of Impeller Outlet and Diffuser Inlet in Stamping and Welding Centrifugal Pump

2012 ◽  
Vol 229-231 ◽  
pp. 2454-2458
Author(s):  
Jian Jun Gan ◽  
Jie Gang Mou ◽  
Shui Hua Zheng ◽  
Bo Zhu
Keyword(s):  
Centrifugal Pump ◽  
Experimental Research ◽  
Static Pressure ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Area Ratio ◽  
Cfd Simulations ◽  
Impeller Outlet ◽  
And Performance

Based on CFD simulations and experimental research, this paper studied the mach of impeller outlet and diffuser inlet in stamping and welding centrifugal pump. The influence of area ratio Y of impeller outlet to diffuser inlet on pump internal flow characteristics and performance was studied. Five different area ratio pump models were analyzed. The results indicate that as the area ratio Y= F3/F2 increase, the velocity of fluid in diffuser inlet decreases continuously, the average static pressure of diffuser outlet increases, and the head and efficiency of the pump are risen. When the area ratio increases from Y=1.48 to Y=3.49, the head increases about 3.0% and the efficiency about 2.0%.

Influence of Screw Centrifugal Inducer on Internal Flow Structure of Vortex Pump

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Hui Quan ◽  
Jing Cheng ◽  
Ying Guo ◽  
Lei Kang ◽  
Guoyi Peng
Keyword(s):  
Energy Conversion ◽  
Flow Structure ◽  
Axial Force ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Good Method ◽  
Power Capacity ◽  
Two Phase ◽  
Pump System ◽  
Vortex Pump

Abstract Installing an inducer upstream of the main impeller is an effective approach for improving the performances of a centrifugal pump. In order to study the influence of inducer on the internal flow characteristics and evolution of vortex pump, the numerical simulation and experimental test of the 150WX-200-20 vortex pump have been done by the principle of computational fluid dynamics, to acquire performance and internal flow structure change of the vortex pump with inducer and without inducer. Based on these, the energy conversion of vortex pump is combined with the changes of the through-flow and circulating-flow of the internal flow structure. Through analyzing the influence of inducer on it, the energy conversion characteristic of vortex pump is revealed. The results show that adding the inducer can guarantee the power capacity of the vortex pump and improve the anticavitation performance, so as to improve the pump head and flows. Equipped with suitable for transporting solid liquid two phase flow of the screw centrifugal inducer, it can effectively weaken the existence of circulating-flow and significantly improve the flow situation in the impeller field. Adding inducer can weaken axial force of vortex pump and enhance stability of pump. And under the condition of no clogging, the conclusions are of great significance for improving the power capacity and fluid energy conversion of the vortex pump. In addition, it is a good method to weaken the axial force of the pump and enhance the stability of the pump system by adding the inducer.

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