Centrifugal Fan Performance With Inlet Clearance

1984 ◽  
Vol 106 (4) ◽  
pp. 906-912 ◽  
Author(s):  
T. Wright
Keyword(s):  
Additional Data ◽  
Volume Flow Rate ◽  
Pressure Rise ◽  
Volume Flow ◽  
Radial Clearance ◽  
Centrifugal Fan ◽  
Stall Margin ◽  
Fan Performance ◽  
Overall Performance ◽  
Range Of Values

This paper describes a systematic study of the influence of the inlet clearance gap on the performance of a centrifugal fan. Overall fan performance in terms of volume flow rate, pressure rise, stall margin, and efficiency were measured over a range of values of the radial clearance between the impeller and the stationary inlet cone. These data have been correlated as functions of lumped clearance parameters. Additional data on velocity surveys in the impeller discharge are presented and discussed in relation to overall performance.

Centrifugal Fan Performance With Distorted Inflows

1984 ◽  
Vol 106 (4) ◽  
pp. 895-900 ◽  
Author(s):  
T. Wright ◽  
S. Madhavan ◽  
J. DiRe
Keyword(s):  
Pressure Rise ◽  
Flow Patterns ◽  
Centrifugal Fan ◽  
Nonuniform Flow ◽  
Fan Performance ◽  
Performance Curves ◽  
Inlet Box

Efforts to quantify degradation of the performance of a centrifugal fan subjected to distorted inflows are presented. The study centered on examination of pressure rise, efficiency, and onset of stall for a backwardly-inclined, airfoil-bladed fan. Nonuniform flow patterns were generated in an adjustable countervane damper assembly installed upstream of the inlet box, and systematic families of performance curves were generated. Results of these tests show that significant degradation in efficiency and pressure rise—as much as 10 to 15 percent—may result from moderately to severely distorted inflow patterns. Onset of stall was significantly influenced by severely distorted inflows.

Peristaltic transport of a conducting Jeffrey fluid in an inclined asymmetric channel

2014 ◽  
Vol 07 (06) ◽  
pp. 1450064 ◽  
Author(s):  
K. Vajravelu ◽  
S. Sreenadh ◽  
G. Sucharitha ◽  
P. Lakshminarayana
Keyword(s):  
Flow Rate ◽  
Magnetic Parameter ◽  
Volume Flow Rate ◽  
Wave Train ◽  
Pressure Rise ◽  
Volume Flow ◽  
Jeffrey Fluid ◽  
Physical Parameters ◽  
Asymmetric Channel ◽  
Inclined Asymmetric Channel

Peristaltic flow of a conducting Jeffrey fluid in an inclined asymmetric channel is investigated. The channel asymmetry is produced by considering a peristaltic wave train on the flexible walls of the channel with different amplitudes and phases. The nonlinear governing equations are solved analytically by a perturbation technique. The expressions for the stream function, axial velocity and the pressure rise per wavelength are determined in terms of the Jeffrey number λ1, the Froude number Fr, the perturbation parameter δ, the angle of inclination θ and the phase difference ϕ. Effects of the physical parameters on the velocity field and the pumping characteristics are discussed. It is observed that the size of the trapping bolus increase with an increase in the magnetic parameter and the volume flow rate. That is, the magnetic parameter and the volume flow rate have strong influence on the trapping bolus phenomenon.

scholarly journals A Mathematical Model for the Flow of a Casson Fluid due to Metachronal Beating of Cilia in a Tube

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
A. M. Siddiqui ◽  
A. A. Farooq ◽  
M. A. Rana
Keyword(s):  
Mathematical Model ◽  
Flow Rate ◽  
Volume Flow Rate ◽  
Pressure Rise ◽  
Cylindrical Tube ◽  
Casson Fluid ◽  
Volume Flow ◽  
System Of Nonlinear Equations ◽  
Dimensional System ◽  
Axial Pressure Gradient

A mathematical model is developed to study the transport mechanism of a Casson fluid flow inspired by the metachronal coordination between the beating cilia in a cylindrical tube. A two-dimensional system of nonlinear equations governing the flow problem is formulated by using axisymmetric cylindrical coordinates and then simplified by employing the long wavelength and low Reynolds number assumptions. Exact solutions are derived for the velocity components, the axial pressure gradient, and the stream function. However, the expressions for the pressure rise and the volume flow rate are evaluated numerically. The features of the flow characteristics such as pumping and trapping are illustrated and discussed with the help of graphs. It is observed that the volume flow rate is influenced significantly by the width of plug flow regionHpas well as the cilia length parameterε. The analysis is also applied and compared with the estimated value of the volume flow rate of epididymal fluid in the ductus efferentes of the human male reproductive tract.

OPTIMIZATION OF AN ULTRATHIN CENTRIFUGAL FAN BASED ON THE TAGUCHI METHOD WITH FUZZY LOGICS

2013 ◽  
Vol 37 (3) ◽  
pp. 449-457
Author(s):  
Kuang-Hung Hsien ◽  
Shyh-Chour Huang
Keyword(s):  
Taguchi Method ◽  
Volume Flow Rate ◽  
Volume Flow ◽  
Performance Characteristics ◽  
Design Parameters ◽  
Optimized Design ◽  
Centrifugal Fan ◽  
Blade Angle ◽  
Original Design ◽  
Index Analysis

This paper presents the use of fuzzy-based Taguchi method to optimize the design of the ultrathin centrifugal fan with multiple performance characteristics. An orthogonal array, the signal-to-noise (S/N) ratio, multiresponse performance index, analysis of variance (ANOVA), and computational-fluid-dynamics were used to study the multiple-objectives in the ultrathin centrifugal fan design. The design parameters, outlet dimensions, inlet dimensions, blade angle, and impeller diameter were optimized with considerations of the performance characteristics, including volume flow ratio, static pressure, and noise. The results demonstrate that volume flow rate of the new design fan was almost 29% larger than that of the original design. This study also identified the optimized design parameters that affect the cooling performance of the centrifugal fan.

Robust Design of an Ultra-Thin Centrifugal Fan on Fuzzy-Based Taguchi Method

2012 ◽  
Vol 605-607 ◽  
pp. 189-192
Author(s):  
Kuang Hung Hsien ◽  
Shyh Chour Huang
Keyword(s):  
Taguchi Method ◽  
Static Pressure ◽  
Fuzzy Inference ◽  
Volume Flow Rate ◽  
Fuzzy Rule ◽  
Volume Flow ◽  
Design Parameters ◽  
Centrifugal Fan ◽  
Blade Angle ◽  
Signal To Noise

The objective of this paper is to apply the Taguchi method with fuzzy inference for optimization the design of an ultrathin centrifugal fan with multiple performance characteristics. The weight of fuzzy rule controlling the system can be adjusted in this study. Taguchi’s concepts of orthogonal array, signal to noise (S/N) ratio, ANOVA, and weight of fuzzy rule were used to study the multiple-objectives in the ultrathin centrifugal fan design. The results showed that: (1) the inlet dimensions have a significant influence on the volume flow rate, whereas outlet dimensions, inlet dimensions and blade angle have a significant effect on the static pressure; (2) appropriate adjustments the weight of fuzzy rule can be obtained a better design parameters for the objective.

Influence of the Sweep Stacking on the Performance of an Axial Fan

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Ayhan Nazmi Ilikan ◽  
Erkan Ayder
Keyword(s):  
Pressure Rise ◽  
Secondary Flows ◽  
Axial Fan ◽  
Negative Effects ◽  
Blade Loading ◽  
Stall Margin ◽  
Negative Effect ◽  
Aerodynamic Parameters ◽  
Overall Performance ◽  
Positive Effect

In modern turbomachinery blade design, nonradial stacking of the profiles is often assumed to be one of the ways to improve the performance of a machine. Instead of stacking the profiles radially, the stacking line is changed by several modifications such as sweep, dihedral, lean, or a combination of these. Nonradial stacking influences secondary flows that have effects on the aerodynamic parameters such as efficiency, pressure rise, blade loading, and stall margin. However, many of the studies in literature are limited by the comparison of two or three cases. This situation leads to conflicting results because a modification may cause a positive effect in one study while in another one, the same modification may have a negative effect. In this study, a modified free vortex axial fan (named as base fan (BF) for this study) is designed first and the profiles of the blades are stacked radially by joining the centroids of the profiles. Second, 45 deg, 30 deg forward sweep (FS) and backward sweep (BS) modifications are applied. The effects of these modifications on aerodynamic performance of the fans are investigated by means of numerical calculations. The results show that FS and BS do not significantly affect the overall performance of the fan at the design flowrate in spite of the occurring modifications of the local blade pressure distribution. However, at low flowrates, FS and BS have positive and negative effects on the fan performance, respectively.

A Comparison of Two Alternative Methods for Defining Fan Performance

1982 ◽  
Vol 104 (1) ◽  
pp. 177-183 ◽  
Author(s):  
P. M. Gerhart ◽  
R. Jorgensen ◽  
J. Kroll
Keyword(s):  
Flow Rate ◽  
Total Pressure ◽  
Performance Test ◽  
Static Pressure ◽  
Volume Flow Rate ◽  
Volume Flow ◽  
The Other ◽  
Alternative Methods ◽  
Performance Variables ◽  
Fan Performance

PTC 11 Committee, the ASME Performance Test Code Committee charged with producing a new test code for large industrial fans, has decided to present code users with two options for expressing fan performance. While one of these options is representative of current U.S. practice, the other option appears to be quite different. The differences center around the definitions of fan flow rate and fan output. Historically, fan flow rate has been defined as the volume flow rate at the fan inlet, and fan output has been defined as either the rise in total pressure across the fan or as the rise from the total pressure at the inlet to the static pressure at the outlet. The alternative method uses the mass flow rate and the “fan specific energy” as the performance variables. If the fan process is incompressible, the two sets of variables produce easily reconciled values; however, if compressibility must be accounted for, subtle differences may arise. This paper examines the assumptions and developments of the two alternative methods of expressing fan performance.

Performance Investigation of Bell Mouth of the Multi-Blade Centrifugal Fan in Floor Standing Air-Conditioner

2012 ◽  
Vol 170-173 ◽  
pp. 2512-2516
Author(s):  
Zhong Min Wan ◽  
Zu Yi Zheng ◽  
Jun Hua Wan ◽  
Jing Liu ◽  
Wen Ming Xu
Keyword(s):  
Volume Flow Rate ◽  
Slope Angle ◽  
Simulation Method ◽  
Volume Flow ◽  
Centrifugal Fan ◽  
Air Conditioner ◽  
Air Volume ◽  
Bell Mouth ◽  
Calculation Results ◽  
Type Calculation

Three types of bell mouth with the inward bell mouths whose exit diameter are larger than the impeller inner diameter of multi-blade centrifugal fan used in floor standing air-conditioner are investigated by using the numerical simulation method. Three bell mouths are as follows: The first type of bell mouth is the inward inlet used in the original air-conditioner. The second type is the inward inlet whose axial height is larger than the first type. The third type is the new mold line inward inlet with smaller slope angle than the first type. Calculation results show that the later two type bell mouths can help to improve air volume flow ratio, reduce the vortex in the back of volute exit and increase the air volume flow rate of 6.8 % and 4.2% respectively. The experimental verification was conducted for the simulation results and the experimental results shows that the air volume rates increase 4.7 % and 3% respectively, the level of noise is constant. The entire performances of the two types are both improved.

Theoretical Interpretation of the CORDIER-Lines for Squirrel-Cage and Cross-Flow Fans

2012 ◽  
Author(s):  
Reinhard Willinger
Keyword(s):  
Flow Rate ◽  
Volume Flow Rate ◽  
Cross Flow ◽  
Pressure Rise ◽  
Low Noise ◽  
Volume Flow ◽  
Theoretical Interpretation ◽  
Outer Diameter ◽  
Flow Angle ◽  
Squirrel Cage

Squirrel-cage fans are centrifugal fans with forward-curved blades. A large number of short blades of thin circular arc sheet metal provide a low diameter drum-type rotor of high axial length. Cross-flow fans have a similar rotor design. However, the flow passes the rotor in radial direction two times. One consequence of the forward-curved blades is that there is more or less no pressure rise in the rotor and the casing has to convert the high absolute rotor exit velocity into a global pressure rise. Both types are used in applications requiring low size, relative high volume flow rates, low costs and low noise at the drawback of relative low efficiency. Volume flow rate, specific isentropic enthalpy difference, rotor outer diameter and rotational speed of a single stage fan can be transformed to speed number and diameter number. For axial, radial and mixed flow fans, a single relationship (CORDIER-diagram) exists and it is well accepted that this line represents “optimum” fan designs with high efficiency. The paper provides a theoretical interpretation of the CORDIER-lines for squirrel-cage and cross-flow fans, since they differ considerably from the classical relationship. Based on velocity triangles and energy transfer, CORDIER-line of squirrel-cage fans depends on absolute inlet flow angle, relative exit flow angle, rotor inlet to exit diameter ratio, relative axial rotor width and circumferential efficiency. Additionally, the CORDIER-line of cross-flow fans depends on the degree of admission. At a distinguished pressure coefficient, a maximum speed number is found, corresponding to maximum volume flow rate.

scholarly journals Numerical Investigations on the Influence of Innovative Hub Geometry Design for Augmented Performance in a Low Speed Centrifugal Fan

2020 ◽  
Author(s):  
Madhwesh N ◽  
K Vasudeva Karanth ◽  
N YAGNESH SHARMA
Keyword(s):  
Significant Contribution ◽  
Research Work ◽  
Pressure Rise ◽  
Centrifugal Fan ◽  
Flow Losses ◽  
Geometry Design ◽  
Inlet Region ◽  
Significant Research ◽  
Computational Fluid Dynamics Cfd ◽  
Overall Performance

Abstract Inlet region of a centrifugal fan is considered as one of the important flow domains which provides air into the impeller with adequate flow incidence. There is a dire need for flow guidance for incoming air in order to minimize induced swirl losses in the vicinity of eye of the impeller. An extrusion type of structure, commonly termed hub, is attached to the impeller of turbo machineswhich is used to reduce inlet turning losses and thereby enhancing the performance of the machine in terms of overall static pressure rise. It is seen from a careful literature survey that there has not been significant research on the effect of hub of various shapes and sizeson performance improvement. Analytical tool like computational fluid dynamics (CFD) capture the physics of flow losses encountered especially at the inlet region. This research work attempts to explore numerically the contributions of hub of hemi-spherical and ellipsoidal shapes and parametrically varied sizes on overall performance of the fan. The analysis shows that amongst hemi-spherical and ellipsoidal hub configurations considered in this work, an optimized ellipsoidal hub configuration is found to yield a significant contribution of about 8.4 % for head coefficient and 8.6 % in relative theoretical efficiency over the hub-less base configuration. Finally correlations are developed for the optimized hub shape configurations.

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