Effects of Impeller Blade Loading on Industrial Centrifugal Compressor Performance and Stability

2010 ◽  
Author(s):  
Min Ji ◽  
Michael Cave ◽  
Donghui Zhang
Keyword(s):  
Flow Field ◽  
Energy Demand ◽  
Performance Test ◽  
High Efficiency ◽  
Oil And Gas Industry ◽  
Centrifugal Impeller ◽  
Experimental Investigations ◽  
Impeller Blade ◽  
Blade Loading ◽  
Compressor Performance

Multistage centrifugal compressors are widely used in the oil and gas industry for various applications. As energy demand increases, the compressor has been challenged to have both high efficiency and broad operating range in order to minimize the life-cycle operation cost. Therefore much effort has been devoted to improve performance of the centrifugal impeller through various design methods. This paper highlights experiences gained in the development of three-dimensional impeller design in an effort combining different design methodologies and experimental investigations. In the present paper, a radial impeller in a medium specific speed range was designed through the conventional direct approach as the baseline. Then, it was redesigned with a different loading profile and a challenged loading magnitude by means of the inverse design method. To assess the two design approaches, the resulting two impellers were manufactured and tested in a closed-loop compressor test rig. The experimental investigation consists of both the performance test and detailed traverse test measuring the flow field downstream of the impeller. The paper presents the comparison of impeller performance and time-averaged data of the downstream flow field between the two impellers. Analysis of the test data illustrates the critical impact of the blade loading on the overall compressor performance and stability.

Experimental and Numerical Investigation of Labyrinth Seal Clearance Impact on Centrifugal Impeller Performance

2015 ◽  
Author(s):  
Russell Marechale ◽  
Min Ji ◽  
Michael Cave
Keyword(s):  
Flow Field ◽  
Performance Test ◽  
Labyrinth Seal ◽  
Working Environment ◽  
Flow Coefficient ◽  
Low Flow ◽  
Centrifugal Impeller ◽  
Leakage Flow ◽  
Compressor Performance ◽  
The Impact

Labyrinth seals are widely used in industrial multistage centrifugal compressors to reduce internal leakage and maintain compressor performance for a prolonged operation time. The leakage flow across the shroud seal of covered impellers and the hub seal of the rotating shaft has an important effect on the compressor performance. The amount of leakage flow is primarily a function of seal running clearances, which is typically designed based on the compressor working environment, such as pressure and temperature conditions. The present paper discusses the experimental and numerical studies of seal clearance impact on the performance and operation of a single stage centrifugal compressor. Two experimental campaigns of running a medium-flow coefficient impeller and a low-flow coefficient impeller with various radial clearances of the impeller shroud and the hub labyrinth seal were conducted based on the configuration of the impeller and the return channel system in a closed-loop compressor test rig. The experimental investigation consists of both the overall stage performance test and the traverse test of the flow field downstream of the impeller using three-hole Cobra probes. Static pressure taps were arranged in the impeller shroud cavity in order to obtain the stream-wise pressure distribution. CFD simulations were then performed to compare with the test results. The paper presents the analysis of test data and simulation results of five arrangements of the impeller shroud and the hub seal radial clearances. The impacts of seal clearance height on stage efficiency and head are quantitatively evaluated. The impact on impeller internal flow field and cavity pressure distributions and swirl angle are discussed. Findings from this study are that efficiency reduction with increased seal clearance was as expected, but impeller Euler work was significantly reduced. CFD simulation was validated as a tool for predicting these effects and provides some understanding of the flow mechanisms.

Improving a Vaned Diffuser for a Given Centrifugal Impeller by 3D Inverse Design

2002 ◽  
Author(s):  
Mehrdad Zangeneh ◽  
Damian Vogt ◽  
Christian Roduner
Keyword(s):  
Flow Field ◽  
Viscous Flow ◽  
Centrifugal Compressor ◽  
Inverse Method ◽  
Flow Distribution ◽  
Inverse Design ◽  
Centrifugal Impeller ◽  
Design Code ◽  
Vaned Diffuser ◽  
Blade Loading

In this paper the application of 3D inverse design code TURBOdesign−1 to the design of the vane geometry of a centrifugal compressor vaned diffuser is presented. For this study the new diffuser is designed to match the flow leaving the conventional impeller, which is highly non-uniform. The inverse method designs the blade geometry for a given specification of thickness and blade loading distribution. The paper describes the choice of loading distribution used in the design as well as the influence of the diffuser inlet flow distribution on the vane geometry and flow field. The flow field in the new diffuser is analysed by a 3D viscous flow code and the result is compared to that of the conventional diffuser. Finally the results of testing the stage performance of the new diffuser is compared with that of the conventional stage.

Centrifugal Compressor Blade Trimming for a Range of Flows

2001 ◽  
Author(s):  
C. Rodgers
Keyword(s):  
Centrifugal Compressor ◽  
Test Performance ◽  
Pressure Ratio ◽  
Performance Characteristics ◽  
Centrifugal Impeller ◽  
Impeller Blade ◽  
Flow Capacity ◽  
Component Test ◽  
Compressor Performance ◽  
Stage Efficiency

Centrifugal impeller blade trimming has long been used in the turbocharger industry to adapt a single impeller casting to a series of flow capacities, but surprisingly little published literature exists on the effects of trimming to compressor performance. This paper is presented as partial remedy, and describes the performance characteristics of a single stage centrifugal compressor designed and tested to cover a range of flow requirements by impeller blade and diffuser vane trimming. Stage and component test performance characteristics are presented for five trimmed flowpath contours covering a flow capacity range of approximately five to one at a DeLaval number of 0.75. The impeller tip diameter was 356mm, and the highest overall stage efficiency measured was 84.8% at an (air) pressure ratio of 1.5.

Impact of Realistic Manufacturing Uncertainties on the Aerodynamic Performance of a Transonic Centrifugal Impeller

2020 ◽  
Author(s):  
Yiming Liu ◽  
Ruihong Qin ◽  
Yaping Ju ◽  
Stephen Spence ◽  
Chuhua Zhang
Keyword(s):  
Flow Field ◽  
Uncertainty Quantification ◽  
High Efficiency ◽  
Leading Edge ◽  
Skewed Distribution ◽  
Machining Process ◽  
High Dimensionality ◽  
Centrifugal Impeller ◽  
High Fidelity ◽  
Clear Understanding

Abstract Centrifugal impellers are inevitably subjected to manufacturing uncertainties during the machining process due to many factors. Such manufacturing uncertainties resulting in geometrical variations lead to impeller performance degradation. For a transonic impeller, the complexity of the flow field may amplify this deterioration. In view of this, it is important to have a clear understanding of the effect caused by manufacturing uncertainties. However, relevant studies are rare and lack consideration of realistic manufacturing uncertainties. Furthermore, the high dimensionality caused by high-fidelity uncertainty model makes the computational fluid dynamics (CFD) unaffordable, making the development of high-efficiency and high-fidelity method for high-dimensionality uncertainty quantification (UQ) problems become urgent. To tackle these limitations, a group of 92 machined centrifugal impellers were scanned, and a statistical model of realistic manufacturing uncertainties was built. With the combination of the CFD simulations and Non–Intrusive Polynomial Chaos (NIPC) methods, the influence of manufacturing uncertainties on the polytropic efficiency and flow field of a transonic centrifugal impeller was quantified. To achieve a good trade-off between the computational efficiency and accuracy for the UQ, a Dual Dimensionality Reduction (DDR) method was proposed, by which the dimensionality of the spatially varying input, i.e., the manufacturing error field, was reduced to 3. The results showed that the manufacturing errors of machined impellers follow Gaussian distributions with a mean error of zero and a shape increased standard deviation near the blade leading edge. The polytropic efficiency of the examined impeller exhibited a negatively skewed distribution and the mean efficiency was reduced by 0.34%. The flow mechanisms behind the performance degradations mainly lay in the increased shock losses near the blade tip and separation losses near the hub. The present study provides a fundamental contribution to the uncertainty quantification of turbomachinery and establishes a theoretical foundation for the development of robust centrifugal impellers.

Structural Design and Numerical Simulation of Flue-Gas Desulfurization Absorption Tower Circulating Pump

2012 ◽  
Author(s):  
Jianrui Liu ◽  
Xiaoke He ◽  
Chenxu Guo ◽  
Haigang Wen ◽  
Zhenjun Gao
Keyword(s):  
Service Life ◽  
Flow Field ◽  
Flue Gas ◽  
Performance Test ◽  
High Efficiency ◽  
Internal Flow ◽  
Pump Efficiency ◽  
Performance Curve ◽  
Pump Performance ◽  
Pump Inlet

Based on the design method of great distortion and appropriate extension to pump inlet, blades of large-scale flue-gas desulphurization absorption tower circulating pump were designed to obtain more suitable blade streamline shape for fluid flow in the internal flow field, the hydro-cyclone loss and noise of pump inlet were decreased while the pump performance and efficiency were improved. An impeller clearance automatic compensation device was added to the front shroud, which ensured the pump working in high efficiency area, and the volute sections 5 through 7 were designed to be double-channel to effectively reduce the radial force. Wear of the pump was greatly reduced and the pump service life was extended by developing a new material M26-23V alloy steel. The pump internal flow field was calculated through k-ε model provided by CFD software Fluent 6.3, and the pump performance was predicted. The pump performance test results showed that the prediction performance curve was consistent with test performance curve. It can be concluded that the pump efficiency at design point reaches up to 85.3%, and the comprehensive technical index meet the design requirements. The pump service life was prolonged by rational structure design and favorable wear resistance.

Effects of Real Gas Model Accuracy and Operating Conditions on Supercritical CO2 Compressor Performance and Flow Field

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Alireza Ameli ◽  
Ali Afzalifar ◽  
Teemu Turunen-Saaresti ◽  
Jari Backman
Keyword(s):  
Flow Field ◽  
Critical Point ◽  
Supercritical Co2 ◽  
High Efficiency ◽  
Significant Proportion ◽  
Operating Conditions ◽  
Working Fluid ◽  
Look Up Table ◽  
Compressor Performance ◽  
The Look

Rankine and Brayton cycles are common energy conversion cycles and constitute the basis of a significant proportion of global electricity production. Even a seemingly marginal improvement in the efficiency of these cycles can considerably decrease the annual use of primary energy sources and bring a significant gain in power plant output. Recently, supercritical Brayton cycles using CO2 as the working fluid have attracted much attention, chiefly due to their high efficiency. As with conventional cycles, improving the compressor performance in supercritical cycles is major route to increasing the efficiency of the whole process. This paper numerically investigates the flow field and performance of a supercritical CO2 centrifugal compressor. A thermodynamic look-up table is coupled with the flow solver, and the look-up table is systematically refined to take into account the large variation of thermodynamic properties in the vicinity of the critical point. Effects of different boundary and operating conditions are also discussed. It is shown that the compressor performance is highly sensitive to the look-up table resolution as well as the operating and boundary conditions near the critical point. Additionally, a method to overcome the difficulties of simulation close to the critical point is explained.

On the Evaluation of Reynolds Number and Relative Surface Roughness Effects on Centrifugal Compressor Performance Based on Systematic Experimental Investigations

1984 ◽  
Vol 106 (2) ◽  
pp. 489-498 ◽  
Author(s):  
H. Simon ◽  
A. Bu¨lska¨mper
Keyword(s):  
Surface Roughness ◽  
Reynolds Number ◽  
Centrifugal Compressor ◽  
Performance Test ◽  
Flow Coefficient ◽  
Experimental Investigations ◽  
Design Calculation ◽  
Roughness Effects ◽  
Number Range ◽  
Compressor Performance

This paper summarizes the results of systematic investigations into the Reynolds number effects. It is based on performance map measurements carried out on a compressor test rig which was constructed primarily for this purpose. The measurements were performed for stages with different flow coefficients (0.004 ≦ φ1 ≦ 0.05), with different gases (air, nitrogen, helium, freon) and in the inlet pressure range 0.2 bar ≦ p1 ≦ 40 bar. By analogy with the turbulent flow in technically rough pipes, semi-empirical correlations are derived concerning the effects of the Reynolds number and the relative surface roughness on the characteristic performance parameters (efficiency, flow coefficient, head coefficient, work coefficient). For the detailed design calculation of individual stages, provision is made for the different effects on the hydraulic flow losses and the disk friction losses. Simplified correlations are given for the conversion of characteristics measured during thermodynamic performance tests. The correlations are applied to various single and multistage compressors, and the results compared with measured performance characteristics in the Reynolds number range 6 × 103 ≦ Ret ≦ 1.1 × 107. The good correspondence obtained forms the basis for recommending the application of these simplified relationships for the improvement of centrifugal compressor performance test codes (e.g. ASME PTC-10 and ISO TC 118).

An investigation of a high-performance centrifugal compressor with a variable map width enhancement slot for proton exchange membrane fuel cell systems in commercial vehicle application

2020 ◽  
Vol 235 (1) ◽  
pp. 288-300
Author(s):  
Jianjiao Jin ◽  
Jianfeng Pan ◽  
Zhigang Lu ◽  
Qingrui Wu ◽  
Lizhong Xu
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Centrifugal Compressor ◽  
Proton Exchange Membrane ◽  
Performance Test ◽  
High Efficiency ◽  
Proton Exchange ◽  
Surge Margin ◽  
Compressor Performance ◽  
Exchange Membrane

Maintaining required performance and rated power output of proton exchange membrane fuel cells while reducing fuel consumption demands and improving efficiencies at the largest parasitic work loss contributor, namely the air compressor. In this paper, we built a high-efficiency one-dimensional match model of centrifugal compressor for proton exchange membrane fuel cells first, which was based on the fuel cell air supply system and the optimal trim factor. And then a variable map width enhancement slot design adjusted by a closed ring was first introduced to extend the surge margin and keep high efficiency. Finally, the compressor with a variable map width enhancement slot was validated at a compressor performance rig and a fuel cell simulation system. The results from compressor performance test rig indicate that the compressor peak efficiency is as high as 77% and the surge margin is enhanced by about 28.1∼ 42.7 %. The simulation results of the fuel cell system indicate the maximum power consumption of the compressor and the H2 consumption of comprehensive adapted world transient vehicle cycle are reduced by nearly 1.6 kW and 4.86%, respectively, in comparison with the baseline screw compressor.

Effects of Real Gas Model Accuracy and Operating Conditions on Supercritical CO2 Compressor Performance and Flow Field

2017 ◽  
Author(s):  
Alireza Ameli ◽  
Ali Afzalifar ◽  
Teemu Turunen-Saaresti ◽  
Jari Backman
Keyword(s):  
Flow Field ◽  
Critical Point ◽  
Supercritical Co2 ◽  
High Efficiency ◽  
Significant Proportion ◽  
Operating Conditions ◽  
Working Fluid ◽  
Look Up Table ◽  
Compressor Performance ◽  
The Look

Rankine and Brayton cycles are common energy conversion cycles and constitute the basis of a significant proportion of global electricity production. Even a seemingly marginal improvement in the efficiency of these cycles can considerably decrease the annual use of primary energy sources and bring a significant gain in power plant output. Recently, supercritical Brayton cycles using CO2 as the working fluid have attracted much attention, chiefly due to their high efficiency. As with conventional cycles, improving the compressor performance in supercritical cycles is major route to increasing the efficiency of the whole process. This paper numerically investigates the flow field and performance of a supercritical CO2 centrifugal compressor. A thermodynamic look-up table is coupled with the flow solver and the look-up table is systematically refined to take into account the large variation of thermodynamic properties in the vicinity of the critical point. Effects of different boundary and operating conditions are also discussed. It is shown that the compressor performance is highly sensitive to the look-up table resolution as well as the operating and boundary conditions near the critical point. Additionally, a method to overcome the difficulties of simulation close to the critical point is explained.

Numerical investigation of deep surge in a centrifugal compressor with vaned diffuser and large plenum

2019 ◽  
Vol 234 (2) ◽  
pp. 143-155
Author(s):  
Zhao Yang ◽  
Xi Guang ◽  
Wang Zhiheng ◽  
Zhang Pengfei
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Centrifugal Compressor ◽  
Deep Understanding ◽  
Internal Flow ◽  
Impeller Blade ◽  
Vaned Diffuser ◽  
Blade Loading ◽  
Transient Feature ◽  
Different Characteristics

As the flow rate decreases from stable point to surge point, the complex unsteady flow phenomenon of surge occurs in a centrifugal compressor, which has a significant influence on vast aspects of a compressor. To advance deep understanding of the feature of the deep surge phenomenon, the RANS/URANS numerical simulation is conducted on a centrifugal compressor with a large plenum to analyze the detailed internal flow field in the compressor together with the macroscopic characteristics of the deep surge cycle. The anticlockwise limit cycle obtained from the simulation is firstly analyzed to show the transient characteristics of the stage. Then the variation of blade torque and axial force is presented to show the transient feature in surge cycle together with the proposed prediction of blade torque versus mass flow rate. Meanwhile, there exist different characteristics of the pressure fluctuation along the streamwise direction of the impeller blade, especially the large variation of blade loading near the trailing edge. And the fluctuation of flow field can respectively suppress or promote the hub-corner separation at the process of acceleration or deceleration region, affecting the development of diffuser stall in the surge cycle. The detailed analysis can be helpful to develop the surge model of lumped parameters and determine the effect of surge on impeller blades or downstream components.

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