Numerical investigations on the effect of volute casing treatment for performance augmentation in a centrifugal fan

2021 ◽  
pp. 095440622110341
Author(s):  
Manjunath L Nilugal ◽  
K Vasudeva Karanth ◽  
Madhwesh N
Keyword(s):  
Total Pressure ◽  
Static Pressure ◽  
Numerical Study ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Centrifugal Fan ◽  
Casing Treatment ◽  
Sliding Mesh ◽  
Optimum Configuration

This article presents the effect of volute chamfering on the performance of a forward swept centrifugal fan. The numerical analysis is performed to obtain the performance parameters such as static pressure rise coefficient and total pressure coefficient for various flow coefficients. The chamfer ratio for the volute is optimized parametrically by providing a chamfer on either side of the volute. The influence of the chamfer ratio on the three dimensional flow domain was investigated numerically. The simulation is carried out using Re-Normalisation Group (RNG) k-[Formula: see text] turbulence model. The transient simulation of the fan system is done using standard sliding mesh method available in Fluent. It is found from the analysis that, configuration with chamfer ratio of 4.4 is found be the optimum configuration in terms of better performance characteristics. On an average, this optimum configuration provides improvement of about 6.3% in static pressure rise coefficient when compared to the base model. This optimized chamfer configuration also gives a higher total pressure coefficient of about 3% validating the augmentation in static pressure rise coefficient with respect to the base model. Hence, this numerical study establishes the effectiveness of optimally providing volute chamfer on the overall performance improvement of forward bladed centrifugal fan.

Investigations Into the Flow Behavior in a Nonparallel Shrouded Diffuser of a Centrifugal Fan for Augmented Performance

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
N. Madhwesh ◽  
K. Vasudeva Karanth ◽  
N. Yagnesh Sharma
Keyword(s):  
Numerical Analysis ◽  
Static Pressure ◽  
Numerical Study ◽  
Flow Behavior ◽  
Pressure Rise ◽  
Radial Pressure ◽  
Vital Role ◽  
Centrifugal Fan ◽  
Energy Transformation ◽  
Pressure Equilibrium

It is a well-known fact that the diffuser of a centrifugal fan plays a vital role in the energy transformation leading to better static pressure rise and efficiency. Many researchers have worked on modified geometry with respect to both impeller and diffuser so as to extract better efficiency of the fan. This paper highlights a unique numerical study on the performance of a centrifugal fan, which has a diffuser having nonparallel shrouds. The shroud geometry is parametrically varied by adopting various convergence ratios (CR) for the nonparallel shrouds encompassing the diffuser passage. It is revealed in the study that there exists an optimal CR for which the performance is improved over the regular parallel shrouded diffuser passage (base model). It is observed from the numerical analysis that for a nonparallel convergent shroud corresponding to a CR of 0.35, a relatively higher head coefficient of 3.6% is obtained when compared to that of the base model. This configuration also yields a higher theoretical efficiency of about 2.1% corroborating the improvement in head coefficient. This study predicts a design prescription for nonparallel diffuser shrouds of a centrifugal fan for augmented performance due to the fact that the converging region accelerates and guides the flow efficiently by establishing radial pressure equilibrium.

Numerical and Experimental Investigation of Return Channel Vane Aerodynamics With Two-Dimensional and Three-Dimensional Vanes

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
A. Hildebrandt ◽  
F. Schilling
Keyword(s):  
Experimental Investigation ◽  
Flow Field ◽  
Static Pressure ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Field Performance ◽  
Two Dimensional ◽  
Flow Angle ◽  
Overall Performance ◽  
Return Channel

The present paper deals with the numerical and experimental investigation of the effect of return channel (RCH) dimensions of a centrifugal compressor stage on the aerodynamic performance. Three different return channel stages were investigated, two stages comprising three-dimensional (3D) return channel blades and one stage comprising two-dimensional (2D) RCH vanes. The analysis was performed regarding both the investigation of overall performance (stage efficiency, RCH total pressure loss coefficient) and detailed flow-field performance. For detailed experimental flow-field investigation at the stage exit, six circumferentially traversed three-hole probes were positioned downstream the return channel exit in order to get two-dimensional flow-field information. Additionally, static pressure wall measurements were taken at the hub and shroud pressure and suction side (SS) of the 2D and 3D return channel blades. The return channel system overall performance was calculated by measurements of the circumferentially averaged 1D flow field downstream the diffuser exit and downstream the stage exit. Dependent on the type of return channel blade, the numerical and experimental results show a significant effect on the flow field overall and detail performance. In general, satisfactory agreement between computational fluid dynamics (CFD)-prediction and test-rig measurements was achieved regarding overall and flow-field performance. In comparison with the measurements, the CFD-calculated stage performance (efficiency and pressure rise coefficient) of all the 3D-RCH stages was slightly overpredicted. Very good agreement between CFD and measurement results was found for the static pressure distribution on the RCH wall surfaces while small CFD-deviations occur in the measured flow angle at the stage exit, dependent on the turbulence model selected.

scholarly journals Three-Dimensional Boundary Layer on a Compressor Rotor Blade at Peak Pressure Rise Coefficient

1986 ◽  
Author(s):  
B. Lakshminarayana ◽  
P. Popovski
Keyword(s):  
Boundary Layer ◽  
Rotor Blade ◽  
Peak Pressure ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Layer Growth ◽  
Leakage Flow ◽  
Suction Surface ◽  
Compressor Rotor

A comprehensive study of the three-dimensional turbulent boundary layer on a compressor rotor blade at peak pressure rise coefficient is reported in this paper. The measurements were carried out at various chordwise and radial locations on a compressor rotor blade using a rotating miniature “V” configuration hot-wire probe. The data are compared with the measurement at the design condition. Substantial changes in the blade boundary layer characteristics are observed, especially in the outer sixteen percent of the blade span. The increased chordwise pressure gradient and the leakage flow at the peak pressure coefficient have a cumulative effect in increasing the boundary layer growth on the suction surface. The leakage flow has a beneficial effect on the pressure surface. The momentum and boundary layer thicknesses increase substantially from those at the design condition, especially near the outer radii of the suction surface.

On Flowfield Periodicity in the NASA Transonic Flutter Cascade: Part II — Numerical Study

2000 ◽  
Author(s):  
R. V. Chima ◽  
E. R. McFarland ◽  
J. R. Wood ◽  
J. Lepicovsky
Keyword(s):  
Static Pressure ◽  
Numerical Study ◽  
Three Dimensional ◽  
Side Wall ◽  
Wave Structure ◽  
Experimental Measurements ◽  
Flow Conditions ◽  
Pressure Sensitive ◽  
Transonic Flutter ◽  
Probe Measurements

The transonic flutter cascade facility at NASA Glenn Research Center was redesigned based on a combined program of experimental measurements and numerical analyses. The objectives of the redesign were to improve the periodicity of the cascade in steady operation, and to better quantify the inlet and exit flow conditions needed for CFD predictions. Part I of this paper describes the experimental measurements, which included static pressure measurements on the blade and endwalls made using both static taps and pressure sensitive paints, cobra probe measurements of the endwall boundary layers and blade wakes, and shadowgraphs of the wave structure. Part II of this paper describes three CFD codes used to analyze the facility, including a multibody panel code, a quasi-three-dimensional viscous code, and a fully three-dimensional viscous code. The measurements and analyses both showed that the operation of the cascade was heavily dependent on the configuration of the sidewalls. Four configurations of the sidewalls were studied and the results are described. For the final configuration, the quasi-three-dimensional viscous code was used to predict the location of mid-passage streamlines for a perfectly periodic cascade. By arranging the tunnel sidewalls to approximate these streamlines, side-wall interference was minimized and excellent periodicity was obtained.

Numerical Flow Analysis in a Subsonic Vaned Radial Diffuser With Leading Edge Redesign

1999 ◽  
Vol 121 (1) ◽  
pp. 119-126 ◽  
Author(s):  
E. Casartelli ◽  
A. P. Saxer ◽  
G. Gyarmathy
Keyword(s):  
Static Pressure ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Leading Edge ◽  
Inverse Design ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Characteristic Lines ◽  
Design Software

The flow field in a subsonic vaned radial diffuser of a single-stage centrifugal compressor is numerically investigated using a three-dimensional Navier–Stokes solver (TASCflow) and a two-dimensional analysis and inverse-design software package (MISES). The vane geometry is modified in the leading edge area (two-dimensional blade shaping) using MISES, without changing the diffuser throughflow characteristics. An analysis of the two-dimensional and three-dimensional effects of two redesigns on the flow in each of the diffuser subcomponents is performed in terms of static pressure recovery, total pressure loss production, and secondary flow reduction. The computed characteristic lines are compared with measurements, which confirm the improvement obtained by the leading edge redesign in terms of increased pressure rise and operating range.

Flow Survey of a Forward Curved Blades Centrifugal Fan for HVAC Applications

2016 ◽  
Author(s):  
Fabio Breviario ◽  
Dario Brivio ◽  
Lucio Cardillo ◽  
Alessandro Corsini ◽  
Giovanni Delibra
Keyword(s):  
Total Pressure ◽  
Acoustic Emissions ◽  
Pressure Rise ◽  
Leading Edge ◽  
Cost Effective ◽  
Centrifugal Fan ◽  
Centrifugal Fans ◽  
Flow Features ◽  
Curved Blade ◽  
New Generation

The advancements in fan technology are nowadays animated by two major drivers: the legal requirements that impose minimum fan efficiency grades for fans sold within European Union (and soon US and Asia), and the market request for better air performance and lower sound emissions. Within HVAC (Heating, Ventilating and Air Conditioning) applications, centrifugal fans with forward curved blades are widely used due to the higher total pressure rise capability and lower acoustic emissions with respect to more efficient backward curved blades. However the continuous rise of minimum fan efficiency grades pushes the manufacturers to develop a new generation of forward curved centrifugal fans, improving previous design. Here the challenge is not only on aerodynamics, but in the overall production process, as squirrel cage fans are characterised by a cost-effective consolidated technology, based on simple blade geometries and easy series manufacturing. For example, the blades usually have circular camber lines, as results of cut cylinders. Thus, once the number of blades and the angle at the leading edge are selected, the chord and the deflection capability are constrained as well. These concurring aspects led industry to include in the design process new tools, in particular CFD, to analyse the flow features of the current generation of fans in order to understand which phenomena are to be either controlled or exploited to increase efficiency and total pressure rise. Here we present a numerical investigation on a forward curved blade centrifugal fan for HVAC applications, to highlight the flow features inside the impeller and in the critical region of coupling with the volute. The analysis was carried out with OpenFOAM, an open-source library for CFD. Computations were performed with the frozen rotor approach and validated against available experimental data.

Investigation of the Flow Field on a Transonic Turbine Nozzle Guide Vane With Rim Seal Cavity Flow Ejection

2009 ◽  
Author(s):  
M. Pau ◽  
G. Paniagua
Keyword(s):  
Flow Field ◽  
Static Pressure ◽  
Numerical Study ◽  
Guide Vane ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Cavity Flow ◽  
Trailing Edge ◽  
Dynamic Simulations ◽  
Purge Flow

Ensuring an adequate life of high pressure turbines requires efficient cooling methods, such as rim seal flow ejection from the stator-rotor wheel space cavity interface, which prevents hot gas ingress into the rotor disk. The present work addresses the potential to improve the efficiency in transonic turbines at certain rim seal ejection rates. To understand this process a numerical study was carried out combining computational fluid dynamic simulations (CFD) and experiments on a single stage axial test turbine. The three dimensional steady CFD analysis was performed modeling the purge cavity flow ejected downstream of the stator blade row, at three flow regimes, subsonic M2 = 0.73, transonic M2 = 1.12 and supersonic M2 = 1.33. Experimental static pressure measurements were used to calibrate the computational model. The main flow field-purge flow interaction is found to be governed by the vane shock structures at the stator hub. The interaction between the vane shocks at the hub and the purge flow has been studied and quantitatively characterized as function of the purge ejection rate. The ejection of 1% of the core flow from the rim seal cavity leads to an increase of the hub static pressure of approximately 7% at the vane trailing edge. This local reduction of the stator exit Mach number decreases the trailing edge losses in the transonic regime. Finally, a numerically predicted loss breakdown is presented, focusing on the relative importance of the trailing edge losses, boundary layer losses, shock losses and mixing losses, as a function of the purge rate ejected. Contrary to the experience in subsonic turbines, results in a transonic model demonstrate that ejecting purge flow improves the vane efficiency due to the shock structures modification downstream of the stator.

3-D Numerical Simulation on Unsteady Turbulent Flow of Rotational Flow Self-Priming Pump

2012 ◽  
Vol 562-564 ◽  
pp. 899-902 ◽  
Author(s):  
Chun Lin Wang ◽  
Tian Fang Zhang ◽  
Chun Lei Zhao ◽  
Dong Liu
Keyword(s):  
Turbulent Flow ◽  
Static Pressure ◽  
Three Dimensional ◽  
Rotational Flow ◽  
Coupled Models ◽  
Simple Arithmetic ◽  
Sliding Mesh ◽  
Static Pressure Distribution ◽  
Mesh Model ◽  
Interior Flow

The three-dimensional unsteady turbulent flow of rotational flow self-priming pump was simulated by using Reynolds time-averaged N-S equations and the standard k-ε turbulent model, sliding mesh model of static-dynamic coupled models and SIMPLE arithmetic. The static pressure distribution of the pump central rotative surface and relative velocity of the impeller central rotative surface in a complete application cycle were analyzed. The rule of instantaneous head in a impeller channel cycle was studied, and the positions of maximal head and minimal head were analyzed. It revealed that the unsteady method can truly simulate the changes of the rotational flow self-priming pump interior flow, and the unsteady characteristic of interior flow in rotational flow self-priming pump is obvious and it changes as the relative position of impeller and volute change. The change is periodical, and its frequency is relate to the impeller number and the rotate speed of the pump.

Calculations of three-dimensional viscous flow in a multiblade centrifugal fan by modelling blade forces

2003 ◽  
Vol 217 (3) ◽  
pp. 287-297 ◽  
Author(s):  
S-J Seo ◽  
K-Y Kim ◽  
S-H Kang
Keyword(s):  
Mathematical Model ◽  
Turbulent Flows ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Centrifugal Fan ◽  
Complex Flows ◽  
Flow Through ◽  
Volume Method ◽  
The Mathematical Model

A numerical study is presented for Reynolds-averaged Navier-Stokes analysis of three-dimensional turbulent flows in a multiblade centrifugal fan. Present work aims at development of a relatively simple analysis method for these complex flows. A mathematical model of impeller forces is obtained from the integral analysis of the flow through the impeller. A finite volume method for discretization of governing equations and a standard k-ɛ model as turbulence closure are employed. For the validation of the mathematical model, the computational results for velocity components, static pressure, and flow angles at the exit of the impeller were compared with experimental data. The comparisons show generally good agreement, especially at higher flow coefficients.

Study of an axial-type fan design technique using an optimization method

2009 ◽  
Vol 223 (3) ◽  
pp. 101-111 ◽  
Author(s):  
C-H Cho ◽  
S-Y Cho ◽  
K-Y Ahn ◽  
Y-C Kim
Keyword(s):  
Total Pressure ◽  
Static Pressure ◽  
Pressure Rise ◽  
Optimization Method ◽  
Operating Pressure ◽  
Design Technique ◽  
Fan Performance ◽  
Target Value ◽  
Design Variables ◽  
Fan Blade

A robust axial-type fan design technique is developed by using an optimization method based on the gradient method. A three-dimensional fan blade was initially designed by stacking several two-dimensional (2D) blade profiles along the spanwise direction. These 2D blade profiles were designed using the free-vortex method and profile parameters such as the incidence, deviation, camber, and so on. The initial fan blade adopts 13 design variables to improve the target value of the fan efficiency or the total pressure. These design variables are used to control the rotor and stator profile for obtaining a better target value. In this study, fan efficiency is chosen as a target objective variable to be maximized, and the total and static pressure on the design point are applied as constraints. These procedures are applied to the design of an axial-type fan that must operate at a mass flowrate of 8.37 kg/s with a minimum total pressure rise of 670 Pa. The optimized fan not only increases the efficiency by 2.9 per cent but also satisfies the required total and static pressure conditions compared with the initially designed fan performance. The optimized fan performance agrees with the experimental results; therefore, this fan design technique can be applied to improve the efficiency and the operating pressure of axial-type fans.

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