Computation and Measurement of the Flow in Axial Flow Fans With Skewed Blades

1999 ◽  
Vol 121 (1) ◽  
pp. 59-66 ◽  
Author(s):  
M. G. Beiler ◽  
T. H. Carolus
Keyword(s):  
Total Pressure ◽  
Design Method ◽  
Power Level ◽  
Three Dimensional ◽  
Axial Flow ◽  
Pressure Rise ◽  
Fast Response ◽  
Test Facility ◽  
Navier Stokes ◽  
Pressure Probe

A numerical analysis of the flow in axial flow fans with skewed blades has been conducted to study the three-dimensional flow phenomena pertaining to this type of blade shape. The particular fans have a low pressure rise and are designed without stator. Initial studies focused on blades skewed in the circumferential direction, followed by investigations of blades swept in the direction of the blade chord. A Navier–Stokes code was used to investigate the flow. The simulation results of several fans were validated experimentally. The three-dimensional velocity field was measured in the fixed frame of reference with a triple sensor hot-film probe. Total pressure distribution measurements were performed with a fast response total pressure probe. The results were analyzed, leading to a design method for fans with swept blades. Forward swept fans designed accordingly exhibited good aerodynamic performance. The sound power level, measured on an acoustic fan test facility, improved.

Measurement and Analysis of Total-Pressure Unsteadiness Data From an Axial-Flow Compressor Stage

1982 ◽  
Vol 104 (2) ◽  
pp. 479-488 ◽  
Author(s):  
W. C. Zierke ◽  
T. H. Okiishi
Keyword(s):  
Energy Transfer ◽  
Total Pressure ◽  
Axial Flow ◽  
Fast Response ◽  
Pressure Probe ◽  
Surface Boundary ◽  
Surface Boundary Layer ◽  
Blade Row ◽  
Measurement And Analysis ◽  
Flow Compressor

A fast-response, total-pressure probe was used with a periodically sampling and averaging data acquisition system to study the unsteady total-pressure field in an axial-flow turbomachine. Periodically unsteady total-pressure data were used to demonstrate some of the ways in which turbomachine blade wake transport and interaction influences the energy transfer involved. Observed trends of periodic variations in local total-pressure values could be explained in terms of the details of energy transfer associated with the different kinds of fluid particles (freestream, wake segment, blade surface boundary layer, mixed) moving through a blade row.

Acoustic Isolation of Fans in Ducts

1966 ◽  
Vol 181 (1) ◽  
pp. 948-965
Author(s):  
A. W. Roberts ◽  
R. E. Luxton
Keyword(s):  
Total Pressure ◽  
Power Level ◽  
Axial Flow ◽  
Pressure Rise ◽  
Low Noise ◽  
Sound Power ◽  
Pressure Losses ◽  
Duct Systems ◽  
Downstream Section ◽  
Sound Pressure Measurement

A method of reducing the sound power radiated downstream from axial flow fans is described and investigated. The normal parallel duct fan housing is replaced by a contoured arrangement. With one type of contour and the use of porous absorbent material the reduction in the downstream overall sound power level is 5 dB, that is, the total sound power is reduced by a factor of three. The attenuation is effective in this case over the full audio frequency range but is largest at frequencies above about 1000 c/s. The total pressure losses in each of the several contoured fan housings investigated are practically identical with those in the usual parallel housing and the fan absorbs no significant additional power. Although commercially available duct noise reduction devices may give higher attenuations than those obtained by the contouring method they usually do so at the expense of quite high total pressure losses. For example, the fan used in this investigation gives a total pressure rise of about 1.4 in water gauge and one commercial type of duct noise attenuator, suitable for use with this fan, introduces a total pressure loss of 0.25 in water gauge. Two basic types of fan housing are investigated. One housing has contoured sections upstream and downstream of the fan rotor and the other is a composite arrangement with the normal parallel duct intake and a contoured downstream section. The effect of the presence of absorber on the performance of these basic types is determined. The acoustic performance of each type of fan housing duct is compared by the use of an ‘in duct’ method of sound pressure measurement. It is stressed that the design of low noise fan/duct systems is economically feasible provided sufficient effort is exerted to find a satisfactory compromise between the required aerodynamic and acoustic performances.

Multi Objective Optimization of a Turbomachinery Blade Using NSGA-II

2007 ◽  
Author(s):  
Abdus Samad ◽  
Kwang-Yong Kim ◽  
Ki-Sang Lee
Keyword(s):  
Total Pressure ◽  
Three Dimensional ◽  
Axial Flow ◽  
Navier Stokes ◽  
Total Efficiency ◽  
Pareto Optimal ◽  
Multi Objective Optimization ◽  
Nsga Ii ◽  
Pareto Optimal Front ◽  
Multi Objective

This work presents numerical optimization for design of a blade stacking line of a low speed axial flow fan with a fast and elitist Non-Dominated Sorting of Genetic Algorithm (NSGA-II) of multi-objective optimization using three-dimensional Navier-Stokes analysis. Reynolds-averaged Navier-Stokes (RANS) equations with k-ε turbulence model are discretized with finite volume approximations and solved on unstructured grids. Regression analysis is performed to get second order polynomial response which is used to generate Pareto optimal front with help of NSGA-II and local search strategy with weighted sum approach to refine the result obtained by NSGA-II to get better Pareto optimal front. Four geometric variables related to spanwise distributions of sweep and lean of blade stacking line are chosen as design variables to find higher performed fan blade. The performance is measured in terms of the objectives; total efficiency, total pressure and torque. Hence the motive of the optimization is to enhance total efficiency and total pressure and to reduce torque.

Inlet Box Structure Optimization of a Large Axial-Flow Fan Using Response Surface Methodology

2020 ◽  
Author(s):  
Jin Xiong ◽  
Yinkun Zhang ◽  
Penghua Guo ◽  
Jingyin Li
Keyword(s):  
Total Pressure ◽  
Design Method ◽  
Orthogonal Design ◽  
Axial Flow ◽  
Pressure Rise ◽  
Aerodynamic Performance ◽  
Design System ◽  
Orthogonal Design Method ◽  
Box Structure ◽  
Inlet Box

Abstract Large axial-flow fans are widely used in many fields. The inlet box is an integral part of large axial-flow fans, and a well-designed inlet box could effectively improve fan efficiency. However, the inlet box structure is complicated, and the existing inlet box design method severely depends on the design experience. In this study, we propose a structure optimization design system based on a surrogate model technique for researching the critical structure parameters of the inlet box and accomplishing aerodynamic performance optimization. As for this expensive optimization problem, the design system contains twice optimization procedures by using the Response Surface Methodology (RSM) with the orthogonal design method. The optimization object is an existing large axial-flow fan. The optimization objective is the total pressure efficiency of the fan, and the total pressure rise is the restriction condition. We generate eighteen different inlet boxes connect with the same impeller and outlet pipe by the orthogonal design method and calculated fan aerodynamic performance by CFX software. After the first optimization, we find the key structural parameters by the sensitivity analysis and the reselect variables total of 25 cases are adopted in a further RSM optimal process. The ultimate surrogate model estimates the fan with the optimal inlet box has a better aerodynamic characteristic and a 6.7% total pressure efficiency rise. Finally, we compare the aerodynamic characteristics of the ultimate design fan and the initial fan by CFD simulation. The numerical results show that: the total pressure efficiency is 6.5% higher than that of the initial impeller, and the pressure rise is 3% higher than that of the initial impeller. The result demonstrates that some most critical parameters of the inlet box structure decide the aerodynamic performance, and the inlet box optimization effectively increases the fan efficiency in the meanwhile.

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.

Unsteady Three-Dimensional Analysis of Inlet Distortion in a Transonic Fan

2006 ◽  
Author(s):  
Peng Sun ◽  
Guotal Feng
Keyword(s):  
Shock Wave ◽  
Total Pressure ◽  
Large Scale ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Inlet Distortion ◽  
Flow Loss ◽  
Large Scale Vortex ◽  
Total Temperature ◽  
Transonic Fan

A time-accurate three-dimensional Navier-Stokes solver of the unsteady flow field in a transonic fan was carried out using "Fluent-parallel" in a parallel supercomputer. The numerical simulation focused on a transonic fan with inlet square wave total pressure distortion and the analysis of result consisted of three aspects. The first was about inlet parameters redistribution and outlet total temperature distortion induced by inlet total pressure distortion. The pattern and causation of flow loss caused by pressure distortion in rotor were analyzed secondly. It was found that the influence of distortion was different at different radial positions. In hub area, transportation-loss and mixing-loss were the main loss patterns. Distortion not only complicated them but enhanced them. Especially in stator, inlet total pressure distortion induced large-scale vortex, which produced backflow and increased the loss. While in casing area, distortion changed the format of shock wave and increased the shock loss. Finally, the format of shock wave and the hysteresis of rotor to distortion were analyzed in detail.

The Effect of Vane Clocking on the Unsteady Flowfield in a One and a Half Stage Transonic Turbine

2007 ◽  
Author(s):  
O. Schennach ◽  
R. Pecnik ◽  
B. Paradiso ◽  
E. Go¨ttlich ◽  
A. Marn ◽  
...  
Keyword(s):  
Laser Doppler Velocimetry ◽  
Three Dimensional ◽  
Fast Response ◽  
Navier Stokes ◽  
Doppler Velocimetry ◽  
Pressure Transducers ◽  
Wake Interactions ◽  
Transonic Turbine ◽  
Response Pressure ◽  
Vane Clocking

The current paper presents the results of numerical and experimental clocking investigations performed in a high-pressure transonic turbine with a downstream vane row. The objective was a detailed analysis of shock and wake interactions in such a 1.5 stage machine while clocking the vanes. Therefore a transient 3D-Navier Stokes calculation was done for two clocking positions and the three dimensional results are compared with Laser-Doppler-Velocimetry measurements at midspan. Additionally the second vane was equipped with fast response pressure transducers to record the instantaneous surface pressure for 20 different clocking positions at midspan.

Three Dimensional Clocking Effects in a One and a Half Stage Transonic Turbine

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
O. Schennach ◽  
J. Woisetschläger ◽  
B. Paradiso ◽  
G. Persico ◽  
P. Gaetani
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Fast Response ◽  
Secondary Flows ◽  
Pressure Probe ◽  
Time Resolved ◽  
Flow Angle ◽  
Aerodynamic Pressure ◽  
Velocity Flow ◽  
Transonic Turbine

This paper presents an experimental investigation of the flow field in a high-pressure transonic turbine with a downstream vane row (1.5 stage machine) concerning the airfoil indexing. The objective is a detailed analysis of the three-dimensional aerodynamics of the second vane for different clocking positions. To give an overview of the time-averaged flow field, five-hole probe measurements were performed upstream and downstream of the second stator. Furthermore in these planes additional unsteady measurements were carried out with laser Doppler velocimetry in order to record rotor phase-resolved velocity, flow angle, and turbulence distributions at two different clocking positions. In the planes upstream of the second vane, the time-resolved pressure field has been measured by means of a fast response aerodynamic pressure probe. This paper shows that the secondary flows of the second vane are significantly modified by the different clocking positions, in connection with the first vane modulation of the rotor secondary flows. An analysis of the performance of the second vane is also carried out, and a 0.6% variation in the second vane loss coefficient has been recorded among the different clocking positions.

Investigation of Loss Impact From Production-Like Features in a Compressor Duct Under Engine Realistic Conditions

2017 ◽  
Author(s):  
Fredrik Wallin ◽  
Mark H. Ross ◽  
Max Rusche ◽  
Scott Morris ◽  
Steven Ray
Keyword(s):  
Surface Roughness ◽  
Total Pressure ◽  
Experimental Testing ◽  
Computational Grid ◽  
Test Facility ◽  
Pressure Probe ◽  
Cfd Analysis ◽  
Roughness Model ◽  
Geometrical Features ◽  
Real Geometry

An experimental and numerical investigation of the flow in a compressor duct with engine-realistic in-production features is presented in this paper. The experimental testing was conducted in the ND-FSCC test facility at University of Notre Dame, Indiana, USA. A baseline duct was also tested for back-to-back comparison. The ducts were heavily instrumented; duct inlet and exit flowfields were scanned using a five-hole pressure probe that provided total pressure, velocities and flow angles. Based on the five-hole probe total pressures, duct losses could be assessed. Furthermore the duct inlet boundary layers were traversed and turbulence intensity levels were assessed. For the CFD analysis of the production-like duct, a highly complex computational grid, resolving all the geometrical features present, was used. A previously validated surface roughness model was used to account for the cast aero-surfaces. Both experimental and numerical results show that there is a significant increase in loss for the production-like duct when compared to the baseline duct loss. The CFD results agree very well with experimental results for the baseline duct, which makes it possible to use the experimental data recorded for the production-like duct to validate CFD tools for real geometry effects, such as interface steps and surface roughness for example.

First Unsteady Pressure Measurements With a Fast Response Cooled Total Pressure Probe in High Temperature Gas Turbine Environments

2010 ◽  
Author(s):  
Mehmet Mersinligil ◽  
Jean-Franc¸ois Brouckaert ◽  
Julien Desset
Keyword(s):  
High Pressure ◽  
Pressure Sensor ◽  
Total Pressure ◽  
Fast Response ◽  
Design Stage ◽  
Absolute Pressure ◽  
Pressure Probe ◽  
Probe Design ◽  
Flame Tube ◽  
Blade Passing Frequency

This paper presents the first experimental engine and test rig results obtained from a fast response cooled total pressure probe. The first objective of the probe design was to favor continuous immersion of the probe into the engine to obtain time series of pressure with a high bandwidth and therefore statistically representative average fluctuations at the blade passing frequency. The probe is water cooled by a high pressure cooling system and uses a conventional piezo-resistive pressure sensor which yields therefore both time-averaged and time-resolved pressures. The initial design target was to gain the capability of performing measurements at the temperature conditions typically found at high pressure turbine exit (1100–1400K) with a bandwidth of at least 40kHz and in the long term at combustor exit (2000K or higher). The probe was first traversed at the turbine exit of a Rolls-Royce Viper turbojet engine, at exhaust temperatures around 750 °C and absolute pressure of 2.1bars. The probe was able to resolve the high blade passing frequency (≈23kHz) and several harmonics up to 100kHz. Besides the average total pressure distributions from the radial traverses, phase-locked averages and random unsteadiness are presented. The probe was also used in a virtual three-hole mode yielding unsteady yaw angle, static pressure and Mach number. The same probe was used for measurements in a Rolls-Royce intermediate pressure burner rig. Traverses were performed inside the flame tube of a kerosene burner at temperatures above 1600 °C. The probe successfully measured the total pressure distribution in the flame tube and typical frequencies of combustion instabilities were identified during rumble conditions. The cooling performance of the probe is compared to estimations at the design stage and found to be in good agreement. The frequency response of the probe is compared to cold shock tube results and a significant increase in the natural frequency of the line-cavity system formed by the conduction cooled screen in front of the miniature pressure sensor were observed.

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