scholarly journals Experimental Investigation of a High Pressure Ratio Aspirated Fan Stage

2004 ◽  
Author(s):  
Ali Merchant ◽  
Jack L. Kerrebrock ◽  
John J. Adamczyk ◽  
Edward Braunsheidel
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
Mass Flow ◽  
Pressure Ratio ◽  
Computational Prediction ◽  
Operating Conditions ◽  
High Pressure Ratio ◽  
Stage Performance ◽  
Design Speed ◽  
Computational Analyses

The experimental investigation of an aspirated fan stage designed to achieve a pressure ratio of 3.4:1 at 1500 feet/sec is presented in this paper. The low-energy viscous flow is aspirated from diffusion-limiting locations on the blades and flowpath surfaces of the stage, enabling a very high pressure ratio to be achieved in a single stage. The fan stage performance was mapped at various operating speeds from choke to stall in a compressor facility at fully simulated engine conditions. The experimentally determined stage performance, in terms of pressure ratio and corresponding inlet mass flow rate, was found to be in good agreement with the 3D viscous computational prediction, and in turn close to the design intent. Stage pressure ratios exceeding 3:1 were achieved at design speed, with an aspiration flow fraction of 3.5% of the stage inlet mass flow. The experimental performance of the stage at various operating conditions, including detailed flowfield measurements, are presented and discussed in the context of the computational analyses. The sensitivity of the stage performance and operability to reduced aspiration flow rates at design and off-design conditions are also discussed.

scholarly journals Experimental Investigation of a High Pressure Ratio Aspirated Fan Stage

2005 ◽  
Vol 127 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Ali Merchant ◽  
Jack L. Kerrebrock ◽  
John J. Adamczyk ◽  
Edward Braunscheidel
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
Mass Flow ◽  
Pressure Ratio ◽  
Computational Prediction ◽  
Operating Conditions ◽  
High Pressure Ratio ◽  
Stage Performance ◽  
Design Speed ◽  
Computational Analyses

The experimental investigation of an aspirated fan stage designed to achieve a pressure ratio of 3.4:1 at 1500 ft/s is presented in this paper. The low-energy viscous flow is aspirated from diffusion-limiting locations on the blades and flowpath surfaces of the stage, enabling a very high pressure ratio to be achieved in a single stage. The fan stage performance was mapped at various operating speeds from choke to stall in a compressor facility at fully simulated engine conditions. The experimentally determined stage performance, in terms of pressure ratio and corresponding inlet mass flow rate, was found to be in good agreement with the 3D viscous computational prediction, and in turn close to the design intent. Stage pressure ratios exceeding 3:1 were achieved at design speed, with an aspiration flow fraction of 3.5% of the stage inlet mass flow. The experimental performance of the stage at various operating conditions, including detailed flowfield measurements, are presented and discussed in the context of the computational analyses. The stage performance and operability at reduced aspiration flow rates at design and off-design conditions are also discussed.

scholarly journals Casing Treatments on a Supersonic Diffuser for High Pressure Ratio Centrifugal Compressors

1982 ◽  
Author(s):  
Y. Ribaud ◽  
P. Avram
Keyword(s):  
High Pressure ◽  
Mass Flow ◽  
Pressure Ratio ◽  
Centrifugal Compressors ◽  
Flow Variation ◽  
High Pressure Ratio ◽  
Supersonic Inlet ◽  
Diffuser Flow ◽  
Supersonic Diffuser ◽  
Casing Treatments

Centrifugal compressors with high pressure ratios from 7 to 10 often have a very slow mass flow margin. Suitable casing treatments, including large openings at the diffuser throat connected to annular plenums, greatly increase the reduced mass flow range of the diffuser during supersonic inlet operation. In the region of reduced mass flow variation, the reduction of the diffuser flow is associated with a drop of the effectiveness. The use of a backswept centrifugal rotor allows the experiment to overcome this penalty.

Design and Experimental Investigation of a Mixed Flow Supersonic Compressor Stage

1995 ◽  
Author(s):  
Wolfgang Elmendorf ◽  
Harald Kurz ◽  
Heinz E. Gallus
Keyword(s):  
Experimental Investigation ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Strong Shock ◽  
Mixed Flow ◽  
High Pressure Ratio ◽  
Flow Deceleration ◽  
Stage Performance ◽  
Future Demands ◽  
Inlet Conditions

Highly loaded transonic and supersonic compressors appear capable of meeting the future demands of small gas turbines and jet engines. Particularly mixed flow compressors, taking advantage of the increasing circumferential blade speed between rotor inlet and exit, represent a good compromise with regard to high pressure ratio and mass flow on the one hand, and favorable performance characteristics and efficiency on the other. However, operating a supersonic rotor as part of a stage involves a stator characterized by high turning angles, supersonic inlet conditions and a strong flow deceleration. In fact, the stator can be identified as the critical component regarding overall stage performance. Based on experimentally determined rotor exit flow conditions, the first part of this paper describes the design of a tandem stator with a strong shock in the stator entrance region, followed by subsonic flow turning and diffusion. The main thrust of this paper is to present the analytical results obtained in connection with the experimental investigation of the complete stage at design and off-design conditions. Rotor and stator flow as well as the overall stage performance are discussed in detail. The concept of the tandem stator proves to be suitable for managing the extremely high aerodynamic loading in the Stator. Experimental results reveal the design goals to be met in general.

Open Design of High Pressure Ratio Radial-Inflow Turbine for Academic Validation

2012 ◽  
Author(s):  
Emilie Sauret
Keyword(s):  
High Pressure ◽  
Pressure Ratio ◽  
Operating Conditions ◽  
Cfd Simulations ◽  
Commercial Software ◽  
High Pressure Ratio ◽  
Open Set ◽  
Wide Range ◽  
Radial Inflow Turbine ◽  
Radial Turbines

Computational Fluid Dynamics (CFD) simulations are widely used in mechanical engineering. Although achieving a high level of confidence in numerical modelling is of crucial importance in the field of turbomachinery, verification and validation of CFD simulations are very tricky especially for complex flows encountered in radial turbines. Comprehensive studies of radial machines are available in the literature. Unfortunately, none of them include enough detailed geometric data to be properly reproduced and so cannot be considered for academic research and validation purposes. As a consequence, design improvements of such configurations are difficult. Moreover it seems that well-developed analyses of radial turbines are used in commercial software but are not available in the open literature especially at high pressure ratios. It is the purpose of this paper to provide a fully open set of data to reproduce the exact geometry of the high pressure ratio single stage radial-inflow turbine used in the Sundstrand Power Systems T-100 Multipurpose Small Power Unit. First, preliminary one-dimensional meanline design and analysis are performed using the commercial software RITAL from Concepts-NREC in order to establish a complete reference test case available for turbomachinery code validation. The proposed design of the existing turbine is then carefully and successfully checked against the geometrical and experimental data partially published in the literature. Then, three-dimensional Reynolds-Averaged Navier-Stokes simulations are conducted by means of the Axcent-PushButton CFD® CFD software. The effect of the tip clearance gap is investigated in detail for a wide range of operating conditions. The results confirm that the 3D geometry is correcty reproduced. It also reveals that the turbine is shocked while designed to give a high-subsonic flow and highlight he importance of the diffuser.

An Investigation of the Performance and Design of the Air Ejector Employing Low-Pressure Air as the Driving Fluid

1950 ◽  
Vol 162 (1) ◽  
pp. 149-166 ◽  
Author(s):  
L. J. Kastner ◽  
J. R. Spooner
Keyword(s):  
High Pressure ◽  
Pressure Ratio ◽  
Initial Pressure ◽  
Low Pressure ◽  
Operating Conditions ◽  
Major Influence ◽  
Engineering Practice ◽  
High Pressure Ratio ◽  
Wide Range ◽  
Air Ejector

The air ejector, in its various forms, is a device which has many applications in engineering practice, and several attempts have been made to analyse its mode of action, some of these having been supported by experimental work. Most of the experimental results available are related to ejectors in which relatively high-pressure steam is utilized as the driving fluid, but even in these cases the information provided is restricted to a narrow field. The investigation described relates to an air ejector employing as the driving fluid air at a relatively low pressure, not exceeding 40 lb. per sq. in. (abs.), and covering a wide range of operating conditions by means of interchangeable nozzles. Two distinct experimental arrangements were built—one for the set of conditions in which the ejector draws in a relatively small quantity of suction fluid and pumps it through a relatively high pressure-ratio, and the other covering conditions in which the quantity of suction fluid is much larger, but the pressure ratio is quite small. For a given initial pressure and quantity of driving fluid, the rate of mass flow of suction fluid depends chiefly on the diameter of the combining tube, in which the driving and suction fluids mix; in the experiments, the ratio of com-bining-tube area to driving-nozzle area was varied in twelve steps, covering a range of area ratios from 1·44 to 1,110·0, and compression ratios ranging from about 3 to about 1·001. Efforts were made to find the best proportions of those parts of the ejector which exert a major influence on performance, and certain conclusions are drawn from the results of the experiments. Theoretical aspects of the problem are briefly discussed.

scholarly journals Analysis of the Transonic Flow at the Inlet of a High Pressure Ratio Centrifugal Impeller

1998 ◽  
Author(s):  
Gernot Eisenlohr ◽  
Peter Dalbert ◽  
Hartmut Krain ◽  
Hartwig Pröll ◽  
Franz-Arno Richter ◽  
...  
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Pressure Ratio ◽  
Centrifugal Impeller ◽  
Performance Measurements ◽  
Design Procedures ◽  
Laser Measurements ◽  
High Pressure Ratio ◽  
Design Speed ◽  
Turbo Compressor

In an industrial research project of German and Swiss Turbo Compressor manufacturers a high pressure ratio centrifugal impeller was designed and investigated. Performance measurements and extensive laser measurements (L2F) of the flow field upstream, inside and downstream of the rotor have been carried out. In addition to that, 3D calculations have been performed, mainly for the design point. Some earlier results have been presented by Krain et al., 1995. With four different viscous 3D-solvers, used in companies of the group, calculations for the design speed were carried out to investigate the suitability of these programs in the various design procedures. Special attention was given to the area from rotor inlet up to the splitter blades. The results for the flow field obtained with the four viscous 3D-Solvers are compared with one another and with the L2F-measurements.

Effects of Reynolds number on the performance of a high pressure-ratio turbocharger compressor

2013 ◽  
Vol 56 (6) ◽  
pp. 1361-1369 ◽  
Author(s):  
XinQian Zheng ◽  
Yun Lin ◽  
BinLin Gan ◽  
WeiLin Zhuge ◽  
YangJun Zhang
Keyword(s):  
Reynolds Number ◽  
High Pressure ◽  
Pressure Ratio ◽  
High Pressure Ratio

Effect of Recirculation Device With Counter Swirl Vane on Performance of High Pressure Ratio Centrifugal Compressor

2011 ◽  
Author(s):  
Hideaki Tamaki
Keyword(s):  
High Pressure ◽  
Mach Number ◽  
Flow Rate ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Negative Slope ◽  
Tip Leakage Flow ◽  
Recirculation Flow ◽  
Operating Range ◽  
High Pressure Ratio

Centrifugal compressors used for turbochargers need to achieve a wide operating range. The author has developed a high pressure ratio centrifugal compressor with pressure ratio 5.7 for a marine use turbocharger. In order to enhance operating range, two different types of recirculation devices were applied. One is a conventional recirculation device. The other is a new one. The conventional recirculation device consists of an upstream slot, bleed slot and the annular cavity which connects both slots. The new recirculation device has vanes installed in the cavity. These vanes were designed to provide recirculation flow with negative preswirl at the impeller inlet, a swirl counterwise to the impeller rotational direction. The benefits of the application of both of the recirculation devices were ensured. The new device in particular, shifted surge line to a lower flow rate compared to the conventional device. This paper discusses how the new recirculation device affects the flow field in the above transonic centrifugal compressor by using steady 3-D calculations. Since the conventional recirculation device injects the flow with positive preswirl at the impeller inlet, the major difference between the conventional and new recirculation device is the direction of preswirl that the recirculation flow brings to the impeller inlet. This study focuses on two effects which preswirl of the recirculation flow will generate. (1) Additional work transfer from impeller to fluid. (2) Increase or decrease of relative Mach number. Negative preswirl increases work transfer from the impeller to fluid as the flow rate reduces. It increases negative slope on pressure ratio characteristics. Hence the recirculation flow with negative preswirl will contribute to stability of the compressor. Negative preswirl also increases the relative Mach number at the impeller inlet. It moves shock downstream compared to the conventional recirculation device. It leads to the suppression of the extension of blockage due to the interaction of shock with tip leakage flow.

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