Results and analysis of a L2F flow field investigation within a high-speed high-pressure centrifugal compressor

1997 ◽  
Vol 6 (3) ◽  
pp. 155-163 ◽  
Author(s):  
I. Trebinjac ◽  
I. Claudin
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Centrifugal Compressor ◽  
High Speed ◽  
Field Investigation

scholarly journals An Investigation of Surge in a High-Speed Centrifugal Compressor Using Digital PIV

2000 ◽  
Vol 123 (2) ◽  
pp. 418-428 ◽  
Author(s):  
Mark P. Wernet ◽  
Michelle M. Bright ◽  
Gary J. Skoch
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
High Speed ◽  
Transient Flow ◽  
Dynamic Pressure ◽  
Rotating Stall ◽  
Transient Pressure ◽  
Pressure Transducers ◽  
Stable Operating ◽  
Particle Imaging

Compressor stall is a catastrophic breakdown of the flow in a compressor, which can lead to a loss of engine power, large pressure transients in the inlet/nacelle, and engine flameout. The implementation of active or passive strategies for controlling rotating stall and surge can significantly extend the stable operating range of a compressor without substantially sacrificing performance. It is crucial to identify the dynamic changes occurring in the flow field prior to rotating stall and surge in order to control these events successfully. Generally, pressure transducer measurements are made to capture the transient response of a compressor prior to rotating stall. In this investigation, Digital Particle Imaging Velocimetry (DPIV) is used in conjunction with dynamic pressure transducers to capture transient velocity and pressure measurements simultaneously in the nonstationary flow field during compressor surge. DPIV is an instantaneous, planar measurement technique that is ideally suited for studying transient flow phenomena in high-speed turbomachinery and has been used previously to map the stable operating point flow field in the diffuser of a high-speed centrifugal compressor. Through the acquisition of both DPIV images and transient pressure data, the time evolution of the unsteady flow during surge is revealed.

FLOW-FIELD INVESTIGATION OF MULTIHOLE SUPERHEATED SPRAYS USING HIGH-SPEED PIV. PART II. AXIAL DIRECTION

2013 ◽  
Vol 23 (2) ◽  
pp. 119-140 ◽  
Author(s):  
Ming Zhang ◽  
Min Xu ◽  
Yuyin Zhang ◽  
Gaoming Zhang ◽  
David J. Cleary
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Axial Direction ◽  
Field Investigation

Investigation of the instability mechanisms in a turbocharger centrifugal compressor with a vaneless diffuser by means of unsteady simulations

2016 ◽  
Vol 231 (11) ◽  
pp. 1558-1567 ◽  
Author(s):  
Xinqian Zheng ◽  
Anxiong Liu ◽  
Zhenzhong Sun
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
High Speed ◽  
Simulation Method ◽  
Great Accuracy ◽  
Rotating Stall ◽  
Tip Clearance ◽  
Vaneless Diffuser ◽  
Unstable Flow ◽  
Low Velocity

The stable-flow range of a compressor is predominantly limited by surge and stall. In this paper, an unsteady simulation method was employed to investigate the instability mechanisms of a high-speed turbocharger centrifugal compressor with a vaneless diffuser. In comparison with the variation in the pressure obtained by dynamic experiments on the same compressor, unsteady simulations show a great accuracy in representing the stall behaviour. The predicted frequency of the rotating stall is 22.5% of the rotor frequency, which agrees with to the value for the high-frequency short-term rotating stall obtained experimentally. By investigating the instability of the flow field, it is found that the unstable flow of the turbocharger compressor at high rotational speeds is caused by the tip clearance leakage flow and the ‘backflow vortices’ originating from the interaction of the incoming flow and the backflow in the tip region of the passages. The asymmetric volute helps to induce the occurrence of stall in certain impeller passages because it generates an asymmetric flow field. The high-pressure low-velocity area from the 180° circumferential position to the 270° circumferential position is dominant and strengthens the backflow at the trailing edge of the impeller, finally triggering the stall.

Design of a High-Speed Rotating Test Rig for Adaptive Seal Systems

2015 ◽  
Author(s):  
Laura S. Beermann ◽  
Corina Höfler ◽  
Hans-Jörg Bauer
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
High Speed ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Parameter Study ◽  
Test Rig ◽  
Swirl Chamber ◽  
Mass Flows ◽  
Gap Width

Gas turbine engines are subject to increased performance and improved efficiency, which leads to rising core temperatures with additional cooling needs. Reducing the parasitic leakage in the secondary flow system is important to meet the challenging requirements. New seal designs have to be tested and optimized at engine like conditions, like high pressure of up to 9 bar and surface speed of up to 280 m/s as well as an adjusted flow field. Flexible seal designs are an innovative approach to reduce leakage mass flows significantly. Axial and radial movements during transient operating conditions can be compensated easily, thus allowing a smaller gap width and minimizing rub and heat load. This paper describes the design and construction of a new rotating test rig facility. To the knowledge of the authors, this is the only test rig with an adjustable gap width and flow field in a high pressure and speed range. The facility is capable of up to 8 bar differential pressure across the seal and up to 4 bar back pressure. The high revolution engine facilitates a surface speed of up to 280 m/s. A traversable casing allows a quick change of the gap width during operation and simulates radial and axial rotor/stator movements in the engine. The seal movement as well as the resulting gap width are measured during operation to fully understand the seal behavior. An important feature of the new test rig is the continuously adjustable pre-swirl system. It has been designed to cover the different flow conditions in the real engine. Therefore, a RANS parameter study of the pre-swirl chamber has been conducted, which shows the adjustability of different pre-swirl ratios for constant and changing inlet mass flows.

Large Eddy Simulation for a Deep Surge Cycle in a High-Speed Centrifugal Compressor With Vaned Diffuser

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
Ibrahim Shahin ◽  
Mohamed Gadala ◽  
Mohamed Alqaradawi ◽  
Osama Badr
Keyword(s):  
High Pressure ◽  
Large Eddy Simulation ◽  
Centrifugal Compressor ◽  
Pressure Fluctuation ◽  
High Speed ◽  
Computational Study ◽  
Mean Flow ◽  
Vaned Diffuser ◽  
Eddy Simulation ◽  
Large Eddy

This paper presents a computational study for a high-speed centrifugal compressor stage with a design pressure ratio equal to 4, the stage consisting of a splittered unshrouded impeller and a wedged vaned diffuser. The aim of this paper is to investigate numerically the modifications of the flow structure during a surge cycle. The investigations are based on the results of unsteady three-dimensional, compressible flow simulations, using large eddy simulation (LES) model. Instantaneous and mean flow field analyses are presented in the impeller inducer and in the vaned diffuser region through one surge cycle time intervals. The computational data compare favorably with the measured data, from the literature, for the same compressor and operational point. The surge event phases are well detected inside the impeller and diffuser. The time-averaged loading on the impeller main blade is maximum near the trialing edge and near the tip. The amplitude of the unsteady pressure fluctuation is maximum for the flow reversal condition and reaches values up to 70% of the dynamic pressure. The diffuser vane exhibits high-pressure fluctuation from the vane leading edge to 50% of the chord length. High-pressure fluctuation is detected during the forward flow recovery condition as a result of the shock wave that moves toward the diffuser outlet.

PIV Investigation of a High Speed Centrifugal Compressor Diffuser: Spanwise and Loading Variations

2008 ◽  
Author(s):  
Beni Cukurel ◽  
Patrick B. Lawless ◽  
Sanford Fleeter
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
High Speed ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Vaned Diffuser ◽  
Operation Conditions ◽  
Diffuser Flow ◽  
Transonic Centrifugal Compressor ◽  
Flow Features

An efficient diffuser is essential to a modern compressor stage, due to its significance in stage performance, durability and operability. To address the need for data that describe the complex, unsteady flow field in a vaned diffuser, Particle Image Velocity is utilized to characterize the spanwise and circumferential variations of the flow features in the vaned diffuser passage of a transonic centrifugal compressor. The spanwise variation in the diffuser flow field is further investigated by comparison of 3 different operating conditions representative of low, nominal and high loading. These data demonstrate that not only the diffuser flow field is highly dependent on the operation conditions, e.g. hub-to-shroud variation increases with loading, but also the circumferential periodicity, created by the highly three dimensional impeller discharge flow, generates a larger unsteadiness towards the hub region of the vaned diffuser.

scholarly journals Experimental Flow Field Investigation in a Centrifugal Compressor Vaned Diffuser

1995 ◽  
Author(s):  
Ali Pinarbasi ◽  
Mark W. Johnson
Keyword(s):  
Kinetic Energy ◽  
Flow Field ◽  
Centrifugal Compressor ◽  
Field Investigation ◽  
Vaneless Diffuser ◽  
Mean Velocity ◽  
Cross Sectional ◽  
Impeller Blade ◽  
Vaned Diffuser ◽  
Flow Angle

The purpose of this study was to improve the understanding of the flow physics in a centrifugal compressor vaned diffuser. A low speed compressor with a 19 bladed backswept impeller and diffuser with 16 wedge vanes was used. The measurements were made at three inter-vane positions and are presented as mean velocity, turbulent kinetic energy and flow angle distributions on eight diffuser cross sectional planes. The impeller blade wakes mix out rapidly within the vaneless space and more rapidly than in an equivalent vaneless diffuser. Although the flow is highly non uniform in velocity at the impeller exit, there is no evidence in the results of any separation from the diffuser vanes. The results do however suggest that the use of twisted vanes within the diffuser would be beneficial in reducing losses.

Sign in / Sign up

Export Citation Format

Share Document