scholarly journals Computational Fluid Dynamic Analysis of Flow Rate Performance of a Small Piezoelectric-Hydraulic Pump

2021 ◽  
Vol 11 (11) ◽  
pp. 4888
Author(s):  
Phuc Nguyen Anh ◽  
Jae-Sung Bae ◽  
Jai-Hyuk Hwang
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Transient Flow ◽  
Fluid Dynamic ◽  
Check Valve ◽  
Internal Flow ◽  
Pump Efficiency ◽  
Rate Performance ◽  
Hydraulic Pump ◽  
Computational Fluid Dynamic Analysis

This paper investigates the transient flow rate performance of small piezoelectric-hydraulic pumps. In a previous study, a small piezoelectric hydraulic pump was designed and developed to be applicable to the braking systems of small- and medium-sized UAVs (unmanned aerial vehicles). To this end, a thin plate spring check valve was designed in order to effectively discharge the flow in a single direction. The flow rate of the piezoelectric-hydraulic pump is an important criterion for evaluating pump efficiency. Therefore, a study on the parameters affecting such a flow rate is necessary to enhance the efficiency of piezoelectric hydraulic pumps used in brake systems. This study on small piezoelectric-hydraulic pumps is performed to accurately predict the flow rate using a CFD (Computational Fluid Dynamics) tool. In other words, an unsteady CFD method is applied to model the transient flow rate characteristics and the internal flow field of the fluid. The visualization of the internal flow field is evaluated for a better understanding of the flow fields inside the pump. Moreover, this work also illustrates the detailed motion of both the inlet and outlet check valves during the pump operation that fully reflects the phase shift between the check valves and the piston motion, all of which affect the flow rate performance of the pump. An experiment of flow rate characteristics was conducted on a designed piezoelectric-hydraulic pump, which verifies the validity of the CFD results.

A physics-based zero-dimensional model for the mass flow rate of a turbocharger compressor with uniform/distorted inlet condition

2018 ◽  
Vol 20 (6) ◽  
pp. 624-639 ◽  
Author(s):  
Kang Song ◽  
Ben Zhao ◽  
Harold Sun ◽  
Weilin Yi
Keyword(s):  
Flow Field ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Fluid Dynamic ◽  
Dimensional Model ◽  
Inlet Pipe ◽  
External Work ◽  
Compressor Wheel ◽  
Inlet Flow

Turbocharger compressor, when fitted to a vehicle, usually operates with a curved inlet pipe which leads to distorted inlet flow field, hence deteriorating compressor flow capability. During the measurement of compressor performance, turbocharger-engine matching and controller design, the inlet flow field is, however, assumed to be uniform, which deviates from the real-world conditions. Consequently, the overall system performance could be compromised if the inlet distortion effect is ignored. To address this issue, in this article, a turbomachinery physics-based zero-dimensional model was proposed for the mass flow rate of a compressor with distorted inlet flow field due to 90° and 180° bent inlet pipe. The non-uniform flow is approximated as two-zone flow field, similar to parallel compressors, with the total pressure deviation between two zones modeled as a function of the flow velocity and pipe geometry. For each flow zone, the corresponding mass flow rate is estimated by approximating each sub-compressor as an adiabatic nozzle, where the fluid is driven by external work delivered by a compressor wheel governed by Euler’s turbomachinery equation. By including turbomachinery physics and compressor geometry information into the modeling, the model achieves high fidelity in compressor map interpretation and extrapolation, which is validated in experiments and the three-dimensional computational fluid dynamic simulation.

Simplified Transient Numerical Model of a Supersonic Jet Impacting a Substrate

2017 ◽  
Author(s):  
Sichang Xu ◽  
Patrick Pomerleau-Perron ◽  
Gary W. Rankin
Keyword(s):  
Flow Field ◽  
Numerical Solutions ◽  
Transient Flow ◽  
Fluid Dynamic ◽  
Supersonic Jet ◽  
Axially Symmetric ◽  
Rotary Valve ◽  
Time Curve ◽  
Jet Impact ◽  
Impact Region

The transient flow field near the surface of a substrate impacted by a pulsating supersonic jet emerging from a long tube is investigated using a simplified axially symmetric numerical approach. In the system being modeled, the pulses are created using a rotary valve located at the tube entrance. This flow situation approximates the conditions existing in the Shock-Induced Cold Spray process for coating surfaces with metallic particles. Previous numerical studies of transient supersonic jets either focused on jets emerging from orifices or did not give details of the complex supersonic flow field in the jet impact region. The current approximate numerical method considers the flow within the long tube and in the jet impact region. The procedure involves two stages. The upstream pressure variation with time is first determined using a one-dimensional compressible flow approximation of the entire tube and rotary valve arrangement. The resulting pressure versus time curve serves as the transient inlet boundary condition for an axially symmetric computational fluid dynamic solution of the flow through the tube and region of jet impact on the substrate. The numerical solutions of substrate pressure on the jet centerline versus time are compared with available experimental results and predict certain general features of the substrate pressure traces. Although the simplified model is only in fair agreement with some aspects of the experimental curves, it is shown to be useful in explaining certain peculiar flow features. With the aid of the numerical solution, an explanation for the movement and instability of the bow shock wave which forms ahead of the substrate is described.

Numerical Research on Flow Field for Petroleum Tar Cutting Pump

2013 ◽  
Author(s):  
Jing-ning Hu ◽  
Jing Wang ◽  
Rengui Gu ◽  
Ying-ying Tian ◽  
Qun Ye
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Tilt Angle ◽  
Fluid Dynamic ◽  
Reference Value ◽  
Flow State ◽  
Solid Concentration ◽  
Two Phase ◽  
Revolution Speed ◽  
Small Flow

In order to study the flow state and distribution of the solid particle in the flow field of petroleum tar cutting pump, the Computational Fluid Dynamic method was used to conduct the numerical simulation of liquid-solid two-phase flow based on Euler-Euler multiphase flow model and standard turbulence equation. The influence of flow rate, revolution speed and tilt angle of stator slot on streamline and distribution of solid concentration were analyzed. The result shows:strong swirl exists in inlet segment in small flow rate, but flow rate has little influence on the solid concentration, so it has no obvious influence on the cutting and grinding efficiency.Grinding efficiency could be improved by increasing revolution speed, but the requirement for the equipment would be higher, so the revolution speed should be determined reasonably. Reducing the tilt angle of stator slot is favor for improving the grinding and cutting efficiency, so it could provide some reference value for the optimal design.

scholarly journals 1D-3D coupling investigation of hydraulic transient for power-supply failure of centrifugal pump-pipe system

2019 ◽  
Vol 21 (5) ◽  
pp. 708-726 ◽  
Author(s):  
Xiaoqin Li ◽  
Xuelin Tang ◽  
Min Zhu ◽  
Xiaoyan Shi
Keyword(s):  
Turbulent Flows ◽  
Flow Rate ◽  
Power Supply ◽  
Nuclear Power ◽  
Transient Flow ◽  
Internal Flow ◽  
Transition Process ◽  
Pipeline System ◽  
Pipe System ◽  
Rotating Speed

Abstract In the pumping station, the main feedwater system and the reactor system of nuclear power plant, power-supply failure causes strong hydraulic transients. One-dimensional method of characteristics (1D-MOC) is used to calculate the transient process in the pipeline system while three-dimensional (3D) computational fluid dynamics is employed to analyze the turbulent flows inside the pump and to obtain the performance parameters of the pump, and the data exchanges on the boundary conditions of the shared interface between 1D and 3D domains are updated based on the MpCCI platform. Based on the equation of motion of the pump motion parts, the relationship between the external characteristics and the internal flow field in the pump is further investigated because the dynamic behavior of the pump and the detailed fluid field evolutions inside the pump are captured during the transition process, and the transient flow rate, rotating speed, and pressure inside the impeller are comprehensively investigated. Meanwhile, compared with the data gained by experiment and traditional 1D-MOC, the relative errors of rotating speed and the flow rate obtained by 1D-3D coupling method are smaller than those by 1D-MOC. Furthermore, the influences of the main coupling parameters and coupling modes on the calculation results are analyzed, and the cause of the deviation is further explained.

Numerical Simulation Applied to Study the Effects of Fractal Tree-Liked Network Channel Designs on PEMFC Performance

2012 ◽  
Vol 488-489 ◽  
pp. 1219-1223 ◽  
Author(s):  
Shan Jen Cheng ◽  
Jr Ming Miao ◽  
Chang Hsien Tai
Keyword(s):  
Fuel Cell ◽  
Pressure Drop ◽  
Flow Field ◽  
Fluid Dynamic ◽  
Flow Distribution ◽  
Flow Channel ◽  
Proton Exchange ◽  
Channel Network ◽  
Computational Fluid Dynamic Analysis ◽  
Network Channel

The effect of pressure drop and the flow-field of inhomogeneous transport of reactions gas are two important issues for bipolar flow channel design in proton exchange membrane fuel cell (PEMFC). A novel design through the imitation of biological development of the topology distribution of fractal tree-liked network channel is the main topic of this research. The effects of different Reynolds numbers and stoichiometric mass flow rate of reaction gas on the flow field distribution of tree-like channels were investigated by three-dimensional computational fluid dynamic analysis. According to numerical simulations, the fractal tree-liked network channel would have an excellent performance on the uniformity of multi-branching flow distribution and lower pressure drop along channels. The new type of fractal tree-liked bionic flow channel network design will be applied to assist in the experimental reference for improving the performance of fuel cell stack system in PEMFC for future.

Numerical Simulation of Counter-Current Flow Field in Double Packing Rotating Packed Bed

2013 ◽  
Vol 561 ◽  
pp. 672-676
Author(s):  
De Dong Hu ◽  
Wen Yan Shan ◽  
Guang Wei Zhu
Keyword(s):  
Flow Field ◽  
Fluid Dynamic ◽  
Internal Flow ◽  
Packed Bed ◽  
Liquid Distribution ◽  
Rotating Speed ◽  
Rotating Packed Bed ◽  
Flow Experiment ◽  
Mass Transfer Equipment ◽  
Counter Current

The rotating packed bed is a new and effective mass transfer equipment. However, because of the complexity fluid flow inside the RPB, the flow experiment are not easy to lead to the deeper understanding on the fluid dynamic in an RPB. To explore the internal flow field distribution of rotating packed bed , the internal flow field in counter-current double packing rotating packed bed was studied. At the same time, the flow field changes in different rotating speed was compared and the liquid distribution between the two layer of packing was performanced.

A Study of Inlet Flow Distortion Effects on Automotive Catalytic Converters

1991 ◽  
Vol 113 (3) ◽  
pp. 419-426 ◽  
Author(s):  
G. Bella ◽  
V. Rocco ◽  
M. Maggiore
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Catalytic Converters ◽  
Flow Distortion ◽  
Local Flow ◽  
Positive Effects ◽  
Local Boundary Condition

This paper will focus on the influence exerted by a nonuniform flow distribution at the inlet of oxidizers to catalytic converters on conversion efficiency evaluated channel by channel. To this aim the flow inside the whole domain, constituted by the exhaust manifold and an elliptic-cross-sectional pipe connecting it with the converter shell, is simulated by means of a three-dimensional fluid-dynamic viscous model. In this way, after assigning typical converter size and geometry (i.e., elliptic) the gas flow rate distribution can be described at its inlet surface, also varying the total mass flow rate. After calculating the flow field at converter inlet by means of a three-dimensional model, evaluation is possible of local flow distortion in comparison with the ideal conditions of constant velocity of the gas entering the honeycomb converter channels. The abovementioned distorted flow field is then assigned as a local boundary condition for another model, developed by the authors, able to describe, through a one-dimensional fluid-dynamic approach, the reacting flow into the converter channels. It was also shown that, due to this flow distortion, honeycomb converters are not uniformly exploited in terms of pollutants of different quantities to be converted in each channel (i.e., a nonuniform exploitation of all the metals coating the ceramic monolith). Finally, the positive effects determined by a diffuser upstream of the converter on flow distribution are analyzed.

Structural Design and Numerical Simulation of Flue-Gas Desulfurization Absorption Tower Circulating Pump

2012 ◽  
Author(s):  
Jianrui Liu ◽  
Xiaoke He ◽  
Chenxu Guo ◽  
Haigang Wen ◽  
Zhenjun Gao
Keyword(s):  
Service Life ◽  
Flow Field ◽  
Flue Gas ◽  
Performance Test ◽  
High Efficiency ◽  
Internal Flow ◽  
Pump Efficiency ◽  
Performance Curve ◽  
Pump Performance ◽  
Pump Inlet

Based on the design method of great distortion and appropriate extension to pump inlet, blades of large-scale flue-gas desulphurization absorption tower circulating pump were designed to obtain more suitable blade streamline shape for fluid flow in the internal flow field, the hydro-cyclone loss and noise of pump inlet were decreased while the pump performance and efficiency were improved. An impeller clearance automatic compensation device was added to the front shroud, which ensured the pump working in high efficiency area, and the volute sections 5 through 7 were designed to be double-channel to effectively reduce the radial force. Wear of the pump was greatly reduced and the pump service life was extended by developing a new material M26-23V alloy steel. The pump internal flow field was calculated through k-ε model provided by CFD software Fluent 6.3, and the pump performance was predicted. The pump performance test results showed that the prediction performance curve was consistent with test performance curve. It can be concluded that the pump efficiency at design point reaches up to 85.3%, and the comprehensive technical index meet the design requirements. The pump service life was prolonged by rational structure design and favorable wear resistance.

scholarly journals Experimental study on fiber suspensions in a curved expansion duct with particle image velocimetry

2012 ◽  
Vol 16 (5) ◽  
pp. 1414-1418 ◽  
Author(s):  
Xiao-Yu Liang ◽  
Huan-Huan Wu ◽  
Cheng-Xu Tu ◽  
Kai Zhang
Keyword(s):  
Particle Image Velocimetry ◽  
Flow Field ◽  
Flow Rate ◽  
Particle Image ◽  
Flow Direction ◽  
Internal Flow ◽  
Concave Wall ◽  
Image Velocimetry ◽  
Inlet Flow Rate ◽  
Convex Wall

The visualization measurement of internal flow field in a curved expansion duct is experimentally studied using particle image velocimetry technology and the influence of flow rate on flow field is analyzed. The streamline distribution and related performance curve in the internal flow field can be figured out through further analysis of experiment data. The results show that fiber orientation is mainly affected by velocity gradient, the fibers near the wall are aligned with the flow direction more quickly than the fibers in intermediate region, and the fibers near the concave wall are more quickly aligned with the flow direction than the convex wall. The larger inlet flow rate which will accordingly lead to increase inlet velocity enables the more quick adaptation and steady of fibers in flow direction.

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