Influence of Secondary Flow Injection Angle on a Fluidic Shock Control Technique

2015 ◽  
Vol 31 (2) ◽  
pp. 674-684 ◽  
Author(s):  
Cheng-hong Li ◽  
Hui-jun Tan ◽  
De-peng Wang
Keyword(s):  
Secondary Flow ◽  
Flow Injection ◽  
Control Technique ◽  
Injection Angle ◽  
Shock Control

scholarly journals Numerical Simulation on the Flow Field in a Turbine Stage with Upstream Flow Injection from the Outer Casing: Effects of the Injection Angle.

2003 ◽  
Vol 46 (1) ◽  
pp. 173-183 ◽  
Author(s):  
Ken-ichi FUNAZAKI ◽  
Carlos Felipe Ferreira FAVARETTO ◽  
Masaya KAMATA ◽  
Tadashi TANUMA
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Injection ◽  
Turbine Stage ◽  
Injection Angle ◽  
Upstream Flow

Stator Diffusion Enhancement Using a Re-Circulating Co-Flowing Steady Jet

2004 ◽  
Author(s):  
David Car ◽  
Nicholas J. Kuprowicz ◽  
Jordi Estevadeordal ◽  
Gecheng Zha ◽  
William Copenhaver
Keyword(s):  
Flow Control ◽  
Secondary Flow ◽  
Power Analysis ◽  
High Speed ◽  
Weight Ratio ◽  
System Level ◽  
Control Technique ◽  
Secondary System ◽  
Availability Analysis ◽  
Flow Stream

This paper will outline a steady flow control technique that augments the diffusion process within a stator passage via a continuous co-flowing secondary flow stream along the suction surface. The technique is similar to that used for flow vectoring in nozzles where a secondary flow stream is used to enhance the diffusion and vectoring of high speed jets. Diffusion factors in excess of 0.95 are simulated and the “penalty” for the secondary system is addressed with an availability and simple power analysis. Losses within the secondary flow stream were included in the availability analysis, but it did not account for losses within a delivery system of this secondary flow. This was accomplished through the ID power analysis which assessed this technique’s impact on the efficiency of an axial compression stage and the sensitivity of this efficiency to the secondary flow system’s efficiency. Also, a system level analysis is presented to assess the merits that may be realized in a notional engine with this type of flow control. Particularly, impacts on specific fuel consumption and thrust-to-weight ratio were addressed. A cascade experiment was performed to demonstrate the concept and was conducted in a blow-down cascade tunnel. Significant improvements in diffusion were qualitatively seen from the DPIV measurements despite limitations in achieving the desired secondary flow conditions.

Performance Improvement of an Asymmetric Twin Scroll Turbocharger Turbine through Secondary Flow Injection

2020 ◽  
Author(s):  
Zheng Liu ◽  
Alessandro Romagnoli ◽  
Torsten Palenschat ◽  
Meng Soon Chiong ◽  
Srithar Rajoo ◽  
...  
Keyword(s):  
Secondary Flow ◽  
Performance Improvement ◽  
Flow Injection

Shock Control Method for Hypersonic Inlets Based on Forebody Secondary Flow Recirculation

AIAA Journal ◽  
2018 ◽  
Vol 56 (6) ◽  
pp. 2124-2130
Author(s):  
Yue Zhang ◽  
Hui-Jun Tan ◽  
Hao Chen ◽  
Wan-Ning Gao ◽  
He-Xia Huang
Keyword(s):  
Secondary Flow ◽  
Control Method ◽  
Flow Recirculation ◽  
Shock Control ◽  
Hypersonic Inlets

Multi-injection turbine housing for turbine performance improvement: A numerical and experimental analysis

2020 ◽  
pp. 095765092094300
Author(s):  
Hao Liu ◽  
Zheng Liu ◽  
Alessandro Romagnoli ◽  
Ricardo F Martinez-Botas ◽  
Srithar Rajoo ◽  
...  
Keyword(s):  
Secondary Flow ◽  
Entropy Generation ◽  
Flow Injection ◽  
Cfd Simulation ◽  
Experimental Testing ◽  
Velocity Ratio ◽  
Suction Side ◽  
Turbine Efficiency ◽  
Turbine Performance ◽  
Percentage Points

Secondary flow injection is a way which allows for the efficiency of a turbomachine to be increased further, after blade design optimizations have already been performed. In this paper, a novel method for improving turbine performance using secondary flow injection through an injection slot over the turbine shroud is investigated. Numerical simulations were conducted on a mixed-flow turbocharger turbine to test the effectiveness of secondary flow injection. An optimization was performed at peak efficiency at 50% turbine design speed to determine the injection setup which gives the highest turbine efficiency. Single-passage simulations for the optimized point showed an increase in efficiency of 2.6 percentage points compared to the baseline turbine. Flow analysis shows that injection partially blocks the flow passage near the blade tip, forcing turbine passage flow to migrate towards the hub. This apparently weakens the hub suction side separation vortex and reduces entropy generation from the vortex. Experimental testing was conducted and used for validation of full-stage turbine computational fluid dynamics (CFD) simulation results. Full-stage turbine CFD results show that with inlet nozzle vanes, secondary flow injection did not result in any visible improvement in the internal flow field and entropy generation, but overall efficiency can be improved by up to 2.28 percentage points at a velocity ratio of 0.75. Without nozzle vanes, however, secondary flow injection resulted in an efficiency improvement of up to 6.79 percentage points by weakening the hub suction side separation vortex and reducing its associated losses. Injection on the vaneless turbine configuration also resulted in a roughly 2 percentage point improvement in the peak turbine efficiency over the vaned turbine configuration. This might be due to more flow energy available to be extracted by the rotor from reduced losses due to the lack of nozzle vanes.

Aero-Thermal Performance of a Rotor Blade Cascade With Stator-Rotor Seal Purge Flow

2012 ◽  
Author(s):  
G. Barigozzi ◽  
F. Fontaneto ◽  
G. Franchini ◽  
A. Perdichizzi ◽  
M. Maritano ◽  
...  
Keyword(s):  
Secondary Flow ◽  
Thermal Performance ◽  
Flow Injection ◽  
Rotor Blade ◽  
Thermal Protection ◽  
Leading Edge ◽  
Pressure Probe ◽  
Blade Cascade ◽  
Purge Flow ◽  
End Wall

The present paper investigates the effects of purge flow from a stator-rotor seal gap on the aerodynamic and thermal performance of a rotor blade cascade. Particular attention is paid to thermal results in the leading edge area that is typically difficult to protect. Experimental tests have been performed on a seven-blade cascade of a high-pressure rotor stage of a real gas turbine at low Mach number (Ma2is = 0.3). To simulate the rotational effect in a linear cascade environment, a number of inclined fins have been installed inside the stator-rotor gap, making the coolant flow to exit with the right tangential velocity component. Tests have been carried out at different blowing conditions, with mass flow rate ratios up to 2.0%. Aerodynamic effects of purge flow on secondary flow structures were surveyed by traversing a 5-hole miniaturized pressure probe in a plane 0.08cax downstream of the trailing edge. Film cooling effectiveness distributions on the end wall platform were obtained by using Thermochromic Liquid Crystals technique. Results allowed to investigate the effect of purge flow injection from the upstream gap on the secondary flows development and on the thermal protection capability. Purge flow injection of 1.0% reduced secondary flow losses and was found to effectively protect the front end wall region, up to about 0.5cax downstream of the leading edge. Increasing the purge flow up to 1.5%–2.0% provided a better thermal protection not only stream wise, but also in the region close to the leading edge because of the weakened washing activity of the horseshoe vortex.

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