scholarly journals The Internal Flow Field and Overall Performance of a Centrifugal Fan Impeller: Experiment and Prediction

Author(s):  
T. Wright ◽  
K. T. S. Tzou ◽  
K. W. Greaves ◽  
S. Madhavan

Analytical and experimental procedures for determining the detailed internal flow behavior in the impeller of a centrifugal fan are presented. Predicted and measured values of both the detailed flow fields and overall performance of the impeller are shown to be in good agreement. The analytical procedures are based on a finite element method to predict the inviscid flow field, coupled to a semi-empirical determination of pressure losses in the impeller based on boundary layer calculations. The experimental work used to validate these predictions uses extensive surface pressure taps in the rotating impeller as well as information from inlet and discharge velocity traverses to determine overall performance. The purpose of this work is the development of accurate and reliable analytical tools for the design of air and gas moving equipment with improved performance and efficiency for the power utility market and heavy industrial applications.

2012 ◽  
Vol 468-471 ◽  
pp. 2255-2258
Author(s):  
Feng Gao ◽  
Wei Yan Zhong

The full flow field model of a widely used multi-blade centrifugal was built, using the CFD method, the steady and unsteady numerical simulation of the inner flow in the fan at different working conditions are presented. The numerical simulation results were validated by contrasting to the experiment results. The results displayed the characteristics of the velocity field, pressure field and pressure fluctuate in the centrifugal fan. The results can provide basis for optimizing the fan design and the internal flow, and have important value of engineering applications in the increase of the overall performance in operation.


Author(s):  
Yahya Dogu ◽  
Mahmut F. Aksit ◽  
Mehmet Demiroglu ◽  
Osman Saim Dinc

The industrial applications of brush seals have been increasing due to their superior sealing performance. Advances in the understanding of seal behavior have been pushing the design limits to higher-pressure load, temperature, surface speed, and rotor excursion levels. The highest sealing performance can be achieved when the bristle pack maintains contact with the rotor surface. However, due to many design and operational constraints, most seals operate with some clearance. This operating clearance cannot be avoided due to rotor runouts, transient operating conditions, or excessive bristle wear. In some applications, a minimum initial clearance is required to ensure a certain amount of flow rate for component cooling or purge flow. Typically, brush seal failure occurs in the form of degraded sealing performance due to increasing seal clearance. The seal performance is mainly characterized by the flow field in close vicinity of the bristle pack, through the seal-rotor clearance, and within the bristle pack. This work investigates the flow field for a brush seal operating with some bristle-rotor clearance. A nonlinear form of the momentum transport equation for a porous medium of the bristle pack has been solved by employing the computational fluid dynamics analysis. The results are compared with prior experimental data. The flow field for the clearance seal is observed to have different characteristics compared to that for the contact seal. Outlined as well are the flow features influencing the bristle dynamics.


1996 ◽  
Vol 118 (2) ◽  
pp. 385-393 ◽  
Author(s):  
M. Zangeneh

A three-dimensional inverse design method in which the blade (or vane) geometry is designed for specified distributions of circulation and blade thickness is applied to the design of centrifugal compressor vaned diffusers. Two generic diffusers are designed, one with uniform inlet flow (equivalent to a conventional design) and the other with a sheared inlet flow. The inlet shear flow effects are modeled in the design method by using the so-called “Secondary Flow Approximation” in which the Bernoulli surfaces are convected by the tangentially mean inviscid flow field. The difference between the vane geometry of the uniform inlet flow and nonuniform inlet flow diffusers is found to be most significant from 50 percent chord to the trailing edge region. The flows through both diffusers are computed by using Denton’s three-dimensional inviscid Euler solver and Dawes’ three-dimensional Navier–Stokes solver under sheared in-flow conditions. The predictions indicate improved pressure recovery and internal flow field for the diffuser designed for shear inlet flow conditions.


Author(s):  
M. Zangeneh

A 3D inverse design method in which the blade (or vane) geometry is designed for specified distributions of circulation and blade thickness is applied to the design of centrifugal compressor vaned diffusers. Two generic diffusers are designed, one with uniform inlet flow (equivalent to a conventional design) and the other with a sheared inlet flow. The inlet shear flow effects are modelled in the design method by using the so-called “Secondary Flow Approximation” in which the Bernoulli surfaces are convected by the tangentially mean inviscid flow field. The difference between the vane geometry of the uniform inlet flow and non-uniform inlet flow diffusers is found to be most significant from 50% chord to the trailing edge region. The flow through both diffusers are computed by using Denton’s 3D inviscid Euler solver and Dawes’ 3D Navier-Stokes solver under sheared inflow conditions. The predictions indicate improved pressure recovery and internal flow field for the diffuser designed for shear inlet flow conditions.


2014 ◽  
Vol 668-669 ◽  
pp. 729-732
Author(s):  
Yu Kun Lv ◽  
Bo Zhang ◽  
Bo Cheng

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.


1990 ◽  
Vol 112 (1) ◽  
pp. 84-90 ◽  
Author(s):  
R. J. Kind ◽  
M. G. Tobin

This paper presents the results of performance measurements and detailed measurements of the mean flow field at rotor inlet and rotor exit in three squirrel-cage fan configurations. The flow-field measurements were taken with a five-hole probe and yield total pressure, static pressure, and the three components of velocity. Measurements were taken for two casing throat areas and for two different rotors. For each configuration the flow field was measured for flow rates below, near, and above the best-efficiency point. Flow patterns are complex and there is reverse flow through the rotor blading even at the best-efficiency operating condition. Although complex, the main features of flow behavior can be understood. They were common to all three fan configurations.


2012 ◽  
Vol 538-541 ◽  
pp. 462-465 ◽  
Author(s):  
Yong Chao Zhang ◽  
Qing Guang Chen ◽  
Wei Bin Wang ◽  
Bin Xie

Aiming at a cross-flow fan used in some kind of air conditioner, the full field 3D model was built, and the numerical simulation of the inner turbulent flow under design condition is resented. The results display the characteristics of flow field in the cross-flow fan, especially the velocity field, pressure field and the velocity distributing before the evaporator. The results can provide basis for optimizing the fan design and the internal flow, and have important value of engineering applications in the increase of the overall performance in operation.


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