Analysis and Design of Centrifugal Blowers for the Pressure Ratio Range 1.2 - 1.8

2021 ◽  
Author(s):  
Jonathon Howard ◽  
Abraham Engeda
Keyword(s):  
Pressure Ratio ◽  
Tangential Velocity ◽  
Design Procedure ◽  
Diameter Ratio ◽  
Flow Coefficient ◽  
Flow Angle ◽  
Blade Passage ◽  
Analysis And Design ◽  
Specific Speed ◽  
Ratio Range

Abstract Centrifugal/centrifugal compressor designs within pressure ratio range of 2.0–4.0 have well-established guidelines for most common gases, and it is possible to determine optimum compressor geometry for numerous applications as characterized by specific speed or flow coefficient. Specific speed can be correlated to various combinations of inlet tip-exit diameter ratio, inlet hub-tip diameter ratio, blade exit back-sweep, and inlet-tip absolute tangential velocity for solid body pre-whirl. For centrifugal compressors in the pressure ratio range of 1.2–1.8, commonly known as blowers, there lacks organized and systematic optimum design procedures. Blowers, among many others uses, are widely used in HVAC, and provide air for ventilation and industrial process requirements. Due to broad applications in industry, blowers comprise an important sub-group of turbomachinery. This paper provides analysis and design data for blowers in the pressure ratio range of 1.2–1.8. Specific speed is determined from the data provided, and accurate correlations to possible achievable maximum efficiencies are established within a good operational range. Furthermore, plots of impeller exit flow angle, inlet tip-exit diameter ratio, inlet hub-tip diameter ratio, head coefficient, and blade exit back-sweep are provided over a range of specific speeds for various tip speeds to permit rapid selection of optimum blower size and shape for a variety of applications. The design procedure follows a method that enables efficient blade passage sizing. When the blower inlet and outlet velocities, diameters, blade widths, and blade angles are determined and fixed, the blade passage and profile will be sized by applying an energy, momentum, and continuity balance analysis. The application of these equations equates the proper pressure and velocity distribution throughout the blower impeller. Generally, the passage is designed to accommodate an optimum prescribed diffusion rate.

Vorticity Dynamics in Axial Compressor Flow Diagnosis and Design

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Yantao Yang ◽  
Hong Wu ◽  
Qiushi Li ◽  
Sheng Zhou ◽  
Jiezhi Wu
Keyword(s):  
Pressure Ratio ◽  
Axial Compressor ◽  
Design Procedure ◽  
Abel Equation ◽  
Navier Stokes ◽  
Design Stage ◽  
Analysis And Design ◽  
Compressor Performance ◽  
Performance Check ◽  
Integrated Performance

It is well recognized that vorticity and vortical structures appear inevitably in viscous compressor flows and have strong influence on the compressor performance. However, conventional analysis and design procedure cannot pinpoint the quantitative contribution of each individual vortical structure to the integrated performance of a compressor, such as the stagnation-pressure ratio and efficiency. We fill this gap by using the so-called derivative-moment transformation, which has been successfully applied to external aerodynamics. We show that the compressor performance is mainly controlled by the radial distribution of azimuthal vorticity, of which an optimization in the through-flow design stage leads to a simple Abel equation of the second kind. The satisfaction of the equation yields desired circulation distribution that optimizes the blade geometry. The advantage of this new procedure is demonstrated by numerical examples, including the posterior performance check by 3D Navier–Stokes simulation.

Performance Investigations of Large Capacity Centrifugal Compressors

1978 ◽  
Author(s):  
H. Mishina ◽  
I. Gyobu
Keyword(s):  
Pressure Ratio ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Design Procedure ◽  
Test Results ◽  
Three Dimensional Flow ◽  
Loss Analysis ◽  
Area Distribution ◽  
Specific Speed ◽  
Sectional Shape

An experimental investigation concerning the optimum relative velocity distribution within impellers, the optimum diffusion ratio of vaned diffusers and the optimum circumferential area distribution, sectional shape of scrolls was carried out using high specific speed shrouded impellers with backward leaning blades. A performance design procedure based on loss analysis and quasi-three-dimensional flow analysis was also developed and modified by introducing experimental results. The design procedure was applied to a 7900-kw four-stage air compressor to demonstrate the usefulness. Field test results of the complete machine showed that the maximum isothermal efficiency was 75 percent with the pressure ratio of 5.96 and the flow rate of 29.3 m3/s.

Multiobjective Hydraulic Cylinder Design

1988 ◽  
Vol 110 (1) ◽  
pp. 81-87 ◽  
Author(s):  
Nestor F. Michelena ◽  
Alice M. Agogino
Keyword(s):  
Stress Ratio ◽  
Pressure Ratio ◽  
Circumferential Stress ◽  
Three Dimensional ◽  
Design Procedure ◽  
Hydraulic Cylinder ◽  
Cross Sectional ◽  
Analysis And Design ◽  
Conflicting Objectives ◽  
Monotonicity Analysis

Monotonicity analysis is used to solve a three-objective optimization problem in which a hydraulic cylinder is to be designed. With the additional application of the Karush-Kuhn-Tucker optimality conditions a reduced symbolic design chart is obtained which is then utilized to obtain parametric numerical results. Two- and three-dimensional parametric Pareto-optimal plots are obtained for the three conflicting objectives: (1) cross-sectional area, (2) circumferential stress ratio and (3) pressure ratio. The analysis and design procedure strengthens and extends the results suggested by previous works.

A Numerical Investigation of Loss Coefficient Variation in Various Incidence Angles in Tandem Blades Cascade

2014 ◽  
Author(s):  
Arash Soltani Dehkharqani ◽  
Masoud Boroomand ◽  
Hamzeh Eshraghi
Keyword(s):  
Pressure Ratio ◽  
Axial Flow ◽  
Suction Side ◽  
Loss Coefficient ◽  
Flow Coefficient ◽  
Flow Angle ◽  
Multi Stage ◽  
Wide Range ◽  
And Performance ◽  
Flow Compressor

There is a severe tendency to reduce weight and increase power of gas turbine. Such a requirement is fulfilled by higher pressure ratio of compressor stages. Employing tandem blades in multi-stage axial flow compressors is a promising methodology to control separation on suction sides of blades and simultaneously implement higher turning angle to achieve higher pressure ratio. The present study takes into account the high flow deflection capabilities of the tandem blades consisting of NACA-65 airfoil with fixed percent pitch and axial overlap at various flow incidence angles. In this regard, a two-dimensional cascade model of tandem blades is constructed in a numerical environment. The inlet flow angle is varied in a wide range and overall loss coefficient and deviation angles are computed. Moreover, the flow phenomena between the blades and performance of both forward and afterward blades are investigated. At the end, the aerodynamic flow coefficient of tandem blades are also computed with equivalent single blades to evaluate the performance of such blades in both design and off-design domain of operations. The results show that tandem blades are quite capable of providing higher deflection with lower loss in a wide range of operation and the base profile can be successfully used in design of axial flow compressor. In comparison to equivalent single blades, tandem blades have less dissipation because the momentum exerted on suction side of tandem blades confines the size of separation zone near trailing edges of blades.

Performance Evaluation of Contra-Rotating Fans Operating Under Different Speed Combinations

2019 ◽  
Author(s):  
Navjot Joshi ◽  
Manas Madasseri Payyappalli ◽  
A. M. Pradeep
Keyword(s):  
Numerical Study ◽  
Pressure Ratio ◽  
Axial Direction ◽  
Flow Coefficient ◽  
Suction Surface ◽  
Flow Angle ◽  
Tip Leakage Vortex ◽  
Stall Inception ◽  
Tip Leakage ◽  
Flow Mechanisms

Abstract One of the advantages of a contra-rotating fan is its possibility to operate both the rotors at different speeds. Owing to this possibility, the performance of a contra-rotating fan can be controlled by operating it at different speed combinations. A numerical study of a low aspect ratio contra-rotating fan in low subsonic regime is carried out under various speed combinations of the rotors. Both steady state and Nonlinear Harmonic (NLH) simulations are performed to identify the important flow mechanisms in the contra-rotating fan. The results show that the diffusion factor of rotor-2 is significantly high towards the hub region which implies that large separations are likely to occur at the hub. The wake of rotor-1 is observed to impinge on the suction surface of rotor-2. Rotor-2 generates a strong suction effect at high rotational speeds and thereby delays the stall inception in the whole stage and shows an improvement in the stage pressure ratio. The upstream effect strongly influences the performance of rotor-1. When rotor-2 rotates at higher rotational speed, due to the suction effect, the flow angle at the exit of rotor-1 decreases which allows the fan to operate at lower flow coefficient. When the suction effect is very strong, it pulls the tip leakage vortex of rotor-1 towards the axial direction. Due to the suction effect, the location of the appearance of tip-leakage vortex moves further downstream. The tip-leakage vortex makes a higher angle with the blade chord at near stall conditions for speed combination Nd – 1.5Nd in contrast to a lower angle for speed combination Nd – 0.5Nd. In summary, the paper describes the performance changes, flow physics and the rotor-rotor interaction mechanisms for different speed combinations of a contra-rotating fan.

Steady State and Transient CFD Studies on Aerodynamic Performance Validation of a High Pressure Turbine

2012 ◽  
Author(s):  
Sridhar Murari ◽  
Sathish Sunnam ◽  
Jong S. Liu
Keyword(s):  
High Pressure ◽  
Total Pressure ◽  
Pressure Ratio ◽  
Aerodynamic Performance ◽  
Detached Eddy Simulation ◽  
High Pressure Turbine ◽  
Predictive Capacity ◽  
Flow Angle ◽  
Analysis And Design ◽  
Eddy Simulation

With the advent of fast computers and availability of less costly memory resources, computational fluid dynamics (CFD) has emerged as a powerful tool for the design and analysis of flow and heat transfer of high pressure turbine stages. CFD gives an insight in to flow patterns that are difficult, expensive or impossible to study using experimental techniques. However, the application of CFD depends on its accuracy and reliability. This requires the CFD code to be validated with laboratory measurements to ensure its predictive capacity. In the continual effort to improve analysis and design techniques, Honeywell has been investigating in the use of CFD to predict the aerodynamic performance of a high pressure turbine. Reynolds Averaged Navier Stokes (RANS), unsteady models like detached eddy simulation (DES), large eddy simulation (LES), and Scale Adaptive Simulation (SAS) are used to predict the aerodynamic performance of a high pressure turbine. Mixing plane approach is used to address the flow data transport across the stationary interface in RANS simulation. The film holes on blade surface and end walls for all the analysis are modeled by using actual film hole modeling technique. The validation is accomplished with the test results of a high pressure turbine, Energy Efficient Engine (E3). The aerodynamic performance data at design point, typical off-design points are taken as test cases for the validation study. One dimensional performance parameters such as corrected mass flow rate, total pressure ratio, cycle efficiency, and two dimensional spanwise distributions of total pressure, total temperature and flow angle that are obtained from CFD results are compared with test data. Streamlines and flow field results at different measurement planes are presented to understand the aerodynamic behavior.

Gas Dynamic Designs of Centrifugal Compressors for Gas Industry

2015 ◽  
Author(s):  
Y. Galerkin ◽  
A. Rekstin ◽  
K. Soldatova ◽  
A. Drozdov
Keyword(s):  
High Efficiency ◽  
Pressure Ratio ◽  
Design Procedure ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Centrifugal Compressors ◽  
Gas Industry ◽  
Design Point ◽  
Optimal Values ◽  
And Performance

Centrifugal compressors for gas industry consume huge amount of energy. As a rule, they are single-shaft, with two or more stages and with comparatively low pressure ratio. Compressors operate at low Mach numbers and high Reynolds numbers. Two design parameters influence mostly stage performances. Stage flow coefficient optimal values lie in range 0.060–0.11. Chosen number of stages establishes value of this coefficient if speed of a rotor rotation is fixed. Design loading factor optimal values are 0.42–0.52. It corresponds to high efficiency, shifts a surge limit far from a design point and makes power maximal in a design point. Some considerations about impeller and diffuser types are presented. Design procedure consists on application of the Universal modeling programs for main dimensions optimization and performance calculations. Q3D non-viscid velocity diagrams are analyzed for optimization of blade configuration. Samples of design are presented, 32 MW single-stage pipeline compressor stage with record efficiency included.

scholarly journals A Simple Calculation Method for Ratio of Relative Velocity Within Centrifugal Impeller Channel

1986 ◽  
Author(s):  
Shimpei Mizuki ◽  
Ichiro Watanabe
Keyword(s):  
Total Pressure ◽  
Relative Velocity ◽  
Pressure Ratio ◽  
Empirical Relationship ◽  
Simple Calculation ◽  
Flow Coefficient ◽  
Centrifugal Impeller ◽  
Simple Method ◽  
Flow Angle ◽  
Total Pressure Ratio

A simple but accurate method of calculating ratio of relative velocities within centrifugal impeller channels is proposed using a one-dimensional flow model, whose major parameters are specific speed, non-dimensional root-mean square radius of the inducer inlet, slip factor, flow coefficient and flow angle at impeller exit. After the non dimensional relative velocity at inducer inlet and that at impeller exit are derived, the ratio of relative velocity at impeller exit to that at inducer inlet is obtained. In addition to this, the ratio is divided into two parts: one ratio for the inducer portion and another ratio for the radial portion of the impeller channel. The computations are conducted both for adiabatic inviscid flow and for two conditions assumed for viscous flow, in which one used an empirical relationship between the total pressure ratio and the peripheral speed of impeller and the other used experimental values for the total pressure ratio as a funtion of the flow rate. By the present simple method, the non-dimensional relative velocities as well as the ratios of the relative velocities for the inlets and the exits of an inducer and an impeller channel are calculated accurately.

Conceptual Design of a Centrifugal Compressor Including Consideration of the Effect of Inlet Prewhirl

1992 ◽  
Author(s):  
A. Whitfield
Keyword(s):  
Conceptual Design ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Design Procedure ◽  
Outer Radius ◽  
Compressor Design ◽  
Dimensional Parameters ◽  
Specific Speed ◽  
Impeller Geometry

A non-dimensional impeller design procedure, including the effect of inlet prewhirl, is described. It is shown that the basic non-dimensional parameters commonly used to present the performance of compressors also provide an adequate basis from which a conceptual design procedure can be developed. The adoption of composite non-dimensional groupings such as specific speed and specific diameter are unnecessary. The design procedure is developed non-dimensionally to provide the appropriate impeller geometry as a ratio of the outer radius, and inlet and discharge blade angles. A compressor design for a pressure ratio of 4 to 1 is used to provide an illustrative example.

Experimental Studies on Stall Behavior in a Single Stage Transonic Axial Flow Compressor

2013 ◽  
Author(s):  
Dilipkumar Bhanudasji Alone ◽  
Subramani Satish Kumar ◽  
Shobhavathy M. Thimmaiah ◽  
Janaki Rami Reddy Mudipalli ◽  
A. M. Pradeep ◽  
...  
Keyword(s):  
Mach Number ◽  
Total Pressure ◽  
Pressure Ratio ◽  
Tangential Velocity ◽  
Axial Flow ◽  
Single Stage ◽  
Flow Angle ◽  
Axial Flow Compressor ◽  
Flow Compressor ◽  
Total Pressure Ratio

This paper describes the study of flow behavior of the transonic compressor stage in un-stalled and stalled conditions. Experiments were carried out in an open circuit single stage transonic axial flow compressor test rig. The test compressor was designed for 1.35 total to total pressure ratio at corrected mass flow rate of 22 kg/s. Both steady and unsteady measurements were carried out. The operating envelop of the compressor was experimentally determined to demark the stable and unstable operating range of the compressor at different operating speeds. Variations in the rotor inlet axial and tangential velocity in the tip region were studied using a calibrated single component hot wire probe. The compressor blade element performance was obtained at full flow and near stall conditions using a three hole aerodynamic probe. The variation in flow parameters like absolute flow angle, axial Mach number, absolute Mach number, tangential Mach number, static and total pressure ratio profiles at the rotor exit were obtained and their variations along the blade height were studied at full flow and near stall conditions. Static pressure variation in the tip region along the rotor chord was studied which showed reduction in slope as stall approached. Hotwire measurements showed abrupt variation in the axial velocity as compared to tangential velocity at stalled condition. It was observed that the flow turned in tangential direction at stall, as tangential component of velocity shows more fluctuations at stall in comparison with unstalled condition. The FFT analysis of the raw signals was performed and it was observed that the nature of the rotating stall was abrupt and stall cell travels nearly at half the rotor speed.

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