Discussion: “Effect of Specific Heat Ratio, Impeller Tip Running Clearance, and Compressor Insulation on High-Pressure-Ratio Centrifugal Compressor Modeling” (Block, J. A., and Runstadler, Jr., P. W., 1975, ASME J. Fluids Eng., 97, pp. 174–179)

1976 ◽  
Vol 98 (1) ◽  
pp. 134-134
Author(s):  
Ronald C. Pampreen
Keyword(s):  
High Pressure ◽  
Specific Heat ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Specific Heat Ratio ◽  
High Pressure Ratio

Effect of Specific Heat Ratio, Impeller Tip Running Clearance, and Compressor Insulation on High-Pressure-Ratio Centrifugal Compressor Modeling

1975 ◽  
Vol 97 (2) ◽  
pp. 174-179
Author(s):  
J. A. Block ◽  
P. W. Runstadler
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Specific Heat ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Specific Heat Ratio ◽  
High Pressure Ratio ◽  
Air Inlet ◽  
Stage Efficiency ◽  
Isentropic Efficiency

Results are displayed which show the effect of gas specific heat ratio, impeller tip running clearance, and compressor insulation on modeling of a high-pressure-ratio compressor’s performance. The data were obtained using a low-speed-of-sound gas and a compressor previously tested extensively in air. Duplication of the air inlet specific heat ratio was found to be essential to modeling the air-equivalent flow rate accurately. Stage pressure ratio and stage efficiency were found to be less sensitive to the accurate replication of the air specific heat ratio. For the compressor tested, stage isentropic efficiency increased as impeller-to-shroud tip running clearance was reduced from 15 to 5 percent of the impeller tip axial depth. The measured stage efficiency was found to depend strongly on the heat transfer between the compressor and surroundings.

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.

Stability Improvement of a High-Pressure Ratio Centrifugal Compressor by Flow Injection

2020 ◽  
Vol 33 (6) ◽  
pp. 04020072
Author(s):  
Wenchao Zhang ◽  
Xiao He ◽  
Baotong Wang ◽  
Zhenzhong Sun ◽  
Xinqian Zheng
Keyword(s):  
High Pressure ◽  
Centrifugal Compressor ◽  
Flow Injection ◽  
Pressure Ratio ◽  
High Pressure Ratio

Unsteady influence of Self Recirculation Casing Treatment (SRCT) on high pressure ratio centrifugal compressor

2016 ◽  
Vol 58 ◽  
pp. 19-29 ◽  
Author(s):  
Yang Mingyang ◽  
Martines-botas Ricardo ◽  
Deng Kangyao ◽  
Zhang Yangjun ◽  
Zheng Xinqian
Keyword(s):  
High Pressure ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Casing Treatment ◽  
High Pressure Ratio

Single Versus Dual Recycle System Dynamics of High Pressure Ratio, Low Inertia Centrifugal Compressor Stations

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
K. K. Botros
Keyword(s):  
High Pressure ◽  
Centrifugal Compressor ◽  
Dynamic Instability ◽  
Pressure Ratio ◽  
Check Valve ◽  
Analytical Methodology ◽  
High Pressure Ratio ◽  
Compressor Surge ◽  
Rapid Transients ◽  
Single Versus

Compression systems are designed and operated in a manner to eliminate or minimize the potential for surge, which is a dynamic instability that is very detrimental to the integrity of the compressor unit. Compressor surge can occur when compressors are subjected to rapid transients such as those occurring following an emergency shutdown (ESD) or a power failure, which in turn, requires fast reaction. To prevent this from occurring, compressor stations are designed with single or dual recycle systems with recycle valves, which are required to open upon ESD. There has been extensive debate and confusion as to whether a single recycle or a dual recycle system is required and the circumstances and the conditions under which one system or the other must be used. This paper discusses this crucial design issue in detail and highlights the parameters affecting the decision to employ either system, particularly for high pressure ratio, low inertia compressors. Parameters such as gas volume capacitance (V) in the recycle path, compressor power train inertia, compressor performance characteristics, the recycle valve coefficient (Cv), prestroke and stroke time, and check valve dynamic characteristic are crucial in determining the conditions for dynamic instabilities. A simple analytical methodology based on the perturbation theory is developed that provides a first-cut analysis to determine if a single recycle system is adequate for a given compression system. The concept of an inertia number is then introduced with a threshold value that determines which recycle system to use. Techniques to circumvent compressor surge following ESD are discussed and their respective effectiveness are highlighted including when and if a delay in the fuel cutoff will be effective. An example of a case study with actual field data of a high pressure ratio centrifugal compressor employed in a natural gas compressor station is presented to illustrate the fundamental concept of single versus dual recycle systems.

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