scholarly journals Mass flow rate effect on a rotating detonation combustor with an axial air injection

Shock Waves ◽  
2021 ◽  
Author(s):  
T. Sato ◽  
F. Chacon ◽  
M. Gamba ◽  
V. Raman
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rate Effect ◽  
Air Injection ◽  
Rotating Detonation ◽  
Flow Rate Effect

Numerical Simulation of Steady Air Injection Flow Control Effects on a Transonic Axial Flow Compressor

2012 ◽  
Vol 224 ◽  
pp. 352-357
Author(s):  
Islem Benhegouga ◽  
Ce Yang
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Leading Edge ◽  
Air Injection ◽  
Axial Flow Compressor ◽  
Blade Tip ◽  
Flow Compressor

In this work, steady air injection upstream of the blade leading edge was used in a transonic axial flow compressor, NASA rotor 37. The injectors were placed at 27 % upstream of the axial chord length at blade tip, the injection mass flow rate is 3% of the chock mass flow rate, and 3 yaw angles were used, respectively -20°, -30°, and -40°. Negative yaw angles were measured relative to the compressor face in opposite direction of rotational speeds. To reveal the mechanism, steady numerical simulations were performed using FINE/TURBO software package. The results show that the stall mass flow can be decreased about 2.5 %, and an increase in the total pressure ratio up to 0.5%.

scholarly journals Numerical Investigation of the Hub-Seal Mass Flow Rate Effect on the Axial Turbine Stage Efficiency

2019 ◽  
Vol 213 ◽  
pp. 02080
Author(s):  
Petr Straka
Keyword(s):  
Numerical Simulation ◽  
Mass Flow Rate ◽  
Compressible Flow ◽  
Mass Flow ◽  
Flow Rate ◽  
Turbine Stage ◽  
Axial Turbine ◽  
Flow Through ◽  
Stage Efficiency ◽  
Flow Rate Effect

The contribution deals with numerical simulation of compressible flow through the axial turbine stage equipped with the hub-seal. The current flowing from the hub-seal has a major impact on the secondary flow in the hub-region of the blade span. The aim of this work is to found a dependency of the efficiency-drop on the hub-seal mass flow rate. Numerical simulation has been made for configuration of experimental axial single-stage reaction turbine.

scholarly journals Detailed Evaluation of the Natural Circulation Mass Flow Rate of Water Propelled by Using an Air Injection

2008 ◽  
Vol 45 (3) ◽  
pp. 238-243 ◽  
Author(s):  
Rae-Joon PARK ◽  
Kwang-Soon HA ◽  
Jae-Cheol KIM ◽  
Seong-Wan HONG ◽  
Sang-Baik KIM
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Natural Circulation ◽  
Air Injection ◽  
Detailed Evaluation

Optimization of the Efficiency of Stall Control Using Air Injection for Centrifugal Compressors—Additional Findings

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Taher Halawa
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Turbines ◽  
Stable Condition ◽  
Tangential Direction ◽  
Air Injection ◽  
Centrifugal Compressors ◽  
Injection Angle ◽  
Stall Control

This study presents additional important findings to the results of the research paper; “Optimization of the efficiency of stall control using air injection for centrifugal compressors” published in the Journal of Engineering for Gas Turbines and Power in 2015 (Halawa, T., Gadala, M. S., Alqaradawi, M., and Badr, O., 2015, “Optimization of the Efficiency of Stall Control Using Air Injection for Centrifugal Compressors,” ASME J. Eng. Gas Turbines Power, 137(7), p. 072604). The aim of this study is to make a fine determination of the injection angle, which provides the best stable condition when the compressor operates close to stall condition. A relatively narrower range of injection angles with smaller intervals was selected comparing to the results of the referred published paper, which clarified that the best injection angle is 30 deg. External air was injected close to the diffuser entrance at the shroud surface. Injection was applied with mass flow rate equals 1.5% of the design compressor inlet mass flow rate with injection angles ranged from 16 deg to 34 deg measured from the tangential direction at the vaneless region. It was found that both of injection angles of 28 deg and 30 deg achieved the best results in terms of compressor stabilization but each one of them has a specific advantage comparing to the other one. Using injection angle of 28 deg provided the lowest kinetic energy losses while the best orientation of the fluid through diffuser resulted when using an injection angle of 30 deg.

scholarly journals Characterizing the Effects of Air Injection on Compressor Performance for Use in Active Control of Rotating Stall

1997 ◽  
Author(s):  
Robert L. Behnken ◽  
Mina Leung ◽  
Richard M. Murray
Keyword(s):  
Hysteresis Loop ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Axial Flow ◽  
Open Loop ◽  
Rotating Stall ◽  
Air Injection ◽  
Loop Control ◽  
Flow Compression

Previous work has developed an air injection controller for rotating stall based on the idea of a shifting compressor characteristic and the Moore-Greitzer three state compressor model. In order to demonstrate this form of control experimentally, a series of open loop tests were performed to measure the performance characteristics of a low speed axial flow compression system when air is injected upstream of the rotor face. The position of the air injection port relative to the hub and the rotor face and the angle relative to the mean axial flow were varied. The tests show that the injection of air has drastic effects on the stalling mass flow rate and on the size of the hysteresis loop associated with rotating stall. The stalling mass flow rate was decreased by 10% and the hysteresis loop was completely eliminated under some conditions. The results of the open loop parametric study were then used to implement a closed loop control strategy based on a shifting characteristic.

Numerical Investigation of Rotating Stall Characteristics and Active Stall Control in Centrifugal Compressors

2014 ◽  
Author(s):  
Taher Halawa ◽  
Mohamed Alqaradawi ◽  
Osama Badr ◽  
Mohamed S. Gadala
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotating Stall ◽  
Air Injection ◽  
Tip Leakage Flow ◽  
Centrifugal Compressors ◽  
Flow Rates ◽  
Injection Angle ◽  
Mass Flow Rates

This paper focuses on providing better view for the understanding of rotating stall phenomenon in centrifugal compressors by using numerical simulations and presents a study of the role of air injection method in delaying stall inception by using different injection parameters aiming at increasing the efficiency of this method. Results showed that the formation of stall begins at the impeller inlet due to early flow separation at low mass flow rates and due to the increase of the turbulence level and the absence of fluid orientation guidance at the vaneless region. The flow weakness causes back flow that results in the formation of the tip leakage flow which causes stall development with time. Results also showed that using air injection at specified locations at the vaneless shroud surface at injection angle of 20° and with injection mass flow rate of 1.5% of the inlet design mass flow rate, can delay the stall onset to happen at lower mass flow rate about 3.8 kg/s comparing with using injection with angle of 10° with different injection mass flow rates and also comparing with the case of no injection.

Numerical Simulation of Stall Development Into Surge and Stall Control Using Air Injection in Centrifugal Compressors

2014 ◽  
Author(s):  
Taher Halawa ◽  
Mohamed Alqaradawi ◽  
Osama Badr ◽  
Mohamed S. Gadala
Keyword(s):  
Numerical Simulation ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Pressure Fluctuations ◽  
Air Injection ◽  
Good Effect ◽  
Sudden Increase ◽  
Centrifugal Compressors ◽  
Surge Margin

This study presents a numerical simulation of the formation of rotating stall and the initiation of surge in order to study the connection between stall and surge in centrifugal compressors. Also, the current paper introduces an optimization of the air injection method as a way to increase the surge margin. Results showed that during stall, the compressor is exposed to velocity and pressure fluctuations varying with time, and these fluctuations are increased suddenly and causing surge initiation. The major part which is responsible for the sudden increase in fluctuations is the vaneless region because it was found that the problem starts at the impeller exit near the shroud surface and then transfers to the impeller inlet. Results also showed that during surge, forces on the impeller blades increase to nearly double of its initial value and then decrease again. By using air injection at the vaneless region with different injection angles, it was found that injection with angle of 30° has a good effect on preventing surge and minimizing the pressure fluctuations comparing to other injection angles results. Results showed finally that the surge margin can be increased by using the injection with angle of 30° and with injection mass flow rate of 1% of the design inlet mass flow rate and this causes the surge limit to shift from 4 kg/s to 3.9 kg/s.

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