Numerical Calculation of Centrifugal Fan 9-19No.4A

2012 ◽  
Vol 614-615 ◽  
pp. 536-540 ◽  
Author(s):  
Fan Nian Meng ◽  
Quan Lin Dong ◽  
Nan Chen ◽  
Yun Qiang Fan
Keyword(s):  
Numerical Calculation ◽  
Flow Field ◽  
Numerical Simulations ◽  
Internal Flow ◽  
Operating Conditions ◽  
Centrifugal Fan ◽  
Performance Curve ◽  
Turbulent Model ◽  
Fan Performance ◽  
Calculation Software

This paper is to simulate the internal flow field in the impeller and the volute of 9-19No.4A fan under different operating conditions. Based on CFD theory and standard two-equation turbulent model, the simulations of turbulent flow between the impeller and the volute under different operating conditions are performed by using the flow calculation software CFX. Numerical results are utilized to perform detailed flow visualization. The results indicate that the fan performance curve of the experiment agree with those of numerical simulations.

Experimental and Numerical Study on Pressure Losses and Flow Fluctuations in a High-Pressure Valve Assembly of Steam Turbine Governing System

2020 ◽  
Author(s):  
Vaclav Slama ◽  
Lukas Mrozek ◽  
Bartolomej Rudas ◽  
David Simurda ◽  
Jindrich Hala ◽  
...  
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Numerical Simulations ◽  
Pressure Loss ◽  
Operational Reliability ◽  
Operating Conditions ◽  
The Real ◽  
Pressure Losses ◽  
Flow Fluctuations ◽  
Valve Assembly

Abstract Aerodynamic measurements and numerical simulations carried out on a model of a high-pressure valve assembly used for nozzle governing of a turbine with 135MW output are described in this paper. Aim of the study is to investigate effects of control valve’s strainers on pressure losses and unsteadiness in the flow field. It is an important task since undesirable flow fluctuations can lead to operational reliability issues. Measurements were carried out in the Aerodynamic laboratory of the Institute of Thermomechanics of the Czech Academy of Sciences (IT) where an aerodynamic tunnel is installed. Numerical simulations were carried out in the Doosan Skoda Power (DSP) Company using ANSYS software tools. The experimental model consists of one of two identical parts of the real valve assembly. It means it consists of an inlet pipeline, a stop valve, a valve chamber with two independent control valves, its diffusers and outlet pipelines. The numerical model consists of both assembly parts and includes also an A-wheel control stage in order to simulate the real turbine operating points. The different lifts of the main cone in each control valve for its useful combinations were investigated. Results were evaluated on the model with control valve’s strainers, which were historically used in order to stabilize the flow, and without them. The results of the experimental measurement were compared with the numerical results in the form of pressure losses prediction. From measured pressure fluctuations, it was found out where and for which conditions a danger of flow instabilities occurs. It can be concluded that there is a border, in terms of operating conditions, where the flow field starts to be unstable and this border is different dependent of the fact whether the control valve’s strainers are used or not. Therefore, the areas of safe and danger operational reliability can be predicted. The influence of the control valve’s strainers on the maximal amplitude of periodic fluctuations appears only for the cases when valves are highly overloaded. For normal operating conditions, there is no difference. As a result, the control valve’s strainers do not have to be used in standard applications of valve assemblies. Furthermore, a loss model for valve pressure loss estimation could be updated. Therefore, a pressure loss should be predicted with a sufficient accuracy for each new turbine bid with similar valve assemblies.

Influences of Splitter Blades on the Centrifugal Fan Performances

1989 ◽  
Author(s):  
Lichuan Gui ◽  
Chuangang Gu ◽  
Hongshou Chang
Keyword(s):  
Solution Method ◽  
Pressure Coefficient ◽  
Internal Flow ◽  
Experimental Result ◽  
Centrifugal Fan ◽  
Fan Performance ◽  
Load Distributions ◽  
Result Show ◽  
Engineering Practices ◽  
Approximate Solution Method

Centrifugal fan and compressors with splitter blades are widely utilized in engineering practices. A detail investigation of the influences of splitter blades on a forward-curved centrifugal fan performances is presented in the paper. The study includes two parts: experiment and numerical calculation. The experiments were produced in a specific impeller with adjustable splitter blades in order to get the performances in different conditions. The internal flow field in the impeller was calculated by means of FEASM (Finite Element Approximate Solution Method, Gu, 1984). The experimental result show that changing the circumferential positions of the splitter blades has a noticeble influence on the fan performance, the incidence of splitter blades also has a certain effect on it, and properly lengthened splitter blades can raise the total pressure coefficient. The velocity and load distributions on the blade surfaces calculated can be used to analyse the phenomena above satisfactorily.

scholarly journals Effect of Inlet Geometry on Fan Performance and Flow Field in a Half-Ducted Propeller Fan

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Pin Liu ◽  
Norimasa Shiomi ◽  
Yoichi Kinoue ◽  
Ying-zi Jin ◽  
Toshiaki Setoguchi
Keyword(s):  
Flow Field ◽  
Flow Measurement ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Internal Flow ◽  
Fan Performance ◽  
Ducted Propeller ◽  
Inlet Geometry ◽  
Blade Tip ◽  
The One

In order to clarify the effect of rotor inlet geometry of half-ducted propeller fan on performance and velocity fields at rotor outlet, the experimental investigation was carried out using a hotwire anemometer. Three types of inlet geometry were tested. The first type is the one that the rotor blade tip is fully covered by a casing. The second is that the front one-third part of blade tip is opened and the rest is covered. The third is that the front two-thirds are opened and the rest is covered. Fan test and internal flow measurement at rotor outlet were conducted about three types of inlet geometry. At the internal flow measurement, a single slant hotwire probe was used and a periodical multisampling technique was adopted to obtain the three-dimensional velocity distributions. From the results of fan test, the pressure-rise characteristic drops at high flowrate region and the stall point shifts to high flowrate region, when the opened area of blade tip increases. From the results of velocity distributions at rotor outlet, the region with high axial velocity moves to radial inwards, the circumferential velocity near blade tip becomes high, and the flow field turns to radial outward, when the opened area increases.

scholarly journals Investigation of the Flow Field in the Vicinity of an Axial Flow Fan During Low Flow Rates

2014 ◽  
Author(s):  
Francois G. Louw ◽  
Theodor W. von Backström ◽  
Sybrand J. van der Spuy
Keyword(s):  
Flow Field ◽  
Numerical Simulations ◽  
Flow Rate ◽  
Axial Flow ◽  
Operating Conditions ◽  
Design Flow ◽  
Low Flow ◽  
Axial Flow Fan ◽  
Free Vortex ◽  
Flow Rates

Large axial flow fans are used in forced draft air cooled heat exchangers (ACHEs). Previous studies have shown that adverse operating conditions cause certain sectors of the fan, or the fan as a whole to operate at very low flow rates, thereby reducing the cooling effectiveness of the ACHE. The present study is directed towards the experimental and numerical analyses of the flow in the vicinity of an axial flow fan during low flow rates. This is done to obtain the global flow structure up and downstream of the fan. A near-free-vortex fan, designed for specific application in ACHEs, is used for the investigation. Experimental fan testing was conducted in a British Standard 848, type A fan test facility, to obtain the fan characteristic. Both steady-state and time-dependent numerical simulations were performed, depending on the operating condition of the fan, using the Realizable k-ε turbulence model. Good agreement is found between the numerically and experimentally obtained fan characteristic data. Using data from the numerical simulations, the time and circumferentially averaged flow field is presented. At the design flow rate the downstream fan jet mainly moves in the axial and tangential direction, as expected for a free-vortex design criteria, with a small amount of radial flow that can be observed. As the flow rate through the fan is decreased, it is evident that the down-stream fan jet gradually shifts more diagonally outwards, and the region where reverse flow occur between the fan jet and the fan rotational axis increases. At very low flow rates the flow close to the tip reverses through the fan, producing a small recirculation zone as well as swirl at certain locations upstream of the fan.

Analysis of Internal Flow Field for Centrifugal Fan in Series

2012 ◽  
Vol 233 ◽  
pp. 96-99
Author(s):  
Ya Jun Fan ◽  
Zhang Xu ◽  
Ding Wensi
Keyword(s):  
Velocity Distribution ◽  
Total Pressure ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Wind Pressure ◽  
Meridian Plane ◽  
Centrifugal Fan ◽  
Fan Performance ◽  
In Series ◽  
The Impact

Centrifugal fan in series with high wind pressure is the key facility of pneumatic transport equipment. To consider the impact of changed conditions on performance of centrifugal fan, internal flow of three-stage centrifugal fan at rated speed in different total pressure conditions is analyzed by CFD software FLUENT6.3 in this paper. Flow characteristics are obtained and the differences of total pressure and velocity distribution in each impeller are analyzed under different conditions, velocity distribution on the meridian plane and section of wind guide plates are compared. Finally, curves of P-Q and P-η at 4600 r/min are forecasted through the analysis of the data, which provide references for reducing impact that condition alteration on fan performance and improving the efficiency of the fan.

scholarly journals Experimental research on flow field of a high head model pump turbine based on PIV test

2020 ◽  
Author(s):  
Demin Liu ◽  
Yongzhi Zhao ◽  
Weilin Xu
Keyword(s):  
Flow Field ◽  
Pressure Pulsation ◽  
Internal Flow ◽  
Operating Conditions ◽  
Head Model ◽  
Test Technique ◽  
Pump Turbine ◽  
Flow Angle ◽  
Operating Condition ◽  
Cavitation Pressure

Abstract Pump turbine operating conditions are complex, mainly including turbine mode and pump mode. Pump turbines have various instability problems during operation, such as S-shaped, pump hump, pressure pulsation and cavitation. PIV (Particle Image Velocimetry) is a very effective test technique for the internal flow field observation of pump turbines. In this paper, the internal flow field of pump hump, cavitation, pressure pulsation and four quadrants of the pump turbine are tested by PIV technology. The experimental observations show that the internal flow on those unstable working conditions of the pump turbine is extremely complicated. Those conditions which the vortex separation is serious and the flow angle is changed is far away the best efficiency working condition. Since the operating condition deviates from the optimal operating condition, the inflow Angle is changed and the inflow Angle is far away from the optimal inflow Angle.And the vortex induces and develops strongly by PIV test. The flow phenomenon are demonstrated at each operating points by PIV test.

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.

The Optimal Research on Impeller Central Location of Centrifugal Fan

2014 ◽  
Vol 668-669 ◽  
pp. 729-732
Author(s):  
Yu Kun Lv ◽  
Bo Zhang ◽  
Bo Cheng
Keyword(s):  
Flow Field ◽  
Static Pressure ◽  
Internal Flow ◽  
Flow Fields ◽  
Centrifugal Fan ◽  
Contrastive Analysis ◽  
Location Optimization ◽  
Central Location ◽  
Center Location ◽  
Variable Condition

Taking the G4-73№8D centrifugal fan as research object and utilizing the software of NUMECA to simulate flow fields of volutes with different radial relative positions, the optimum central location of the fan impeller was obtained. The contrastive analysis of internal flow field which of the original and impeller center location optimization fan was under the rated and variable condition, showed that the optimized fan enhanced impeller and volute casing radial adaptive and the efficiency and export static pressure of optimized fan were improved.

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