Parameterization and optimization design of a two-dimensional axisymmetric hypersonic inlet

2021 ◽  
pp. 095441002110295
Author(s):  
Shangcheng Xu ◽  
Yi Wang ◽  
Zhenguo Wang ◽  
Xiaoqiang Fan ◽  
Bing Xiong
Keyword(s):  
Total Pressure ◽  
Optimization Design ◽  
Separation Bubble ◽  
Pressure Recovery ◽  
Two Dimensional ◽  
Recovery Coefficient ◽  
Hypersonic Inlet ◽  
Contraction Ratio ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient

Optimization method, as a promising way to improve inlet aerodynamic performance, has received increasing attention. The present research is undertaken to design a two-dimensional axisymmetric hypersonic inlet using parametric optimization. The inlet configuration is parameterized and optimized in consideration of total pressure recovery and starting performance. A Pareto front is obtained by solving the multi-objective optimization problem. Then, the flow structures of the optimized inlets are analyzed and the starting performances are evaluated. Results show that the total pressure loss mainly occurs in the internal contraction section, especially near the inlet entrance, and therefore the total pressure recovery coefficient can be greatly improved by decreasing external compression. As a result, the guidance for designing high-performance inlets is concluded. Besides, it is found that as the internal contraction ratio increases, the inlet starting ability becomes worse, which attributes to the larger separation bubble at the inlet entrance. Finally, the total pressure recovery coefficient and the starting Mach number of the optimized inlets are obtained, which can be a reference for engineering design.

scholarly journals Influence of Propeller Slipstream on the Flow Field of S-Shaped Intake

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Shuili Ren ◽  
Peiqing Liu
Keyword(s):  
Flow Field ◽  
Total Pressure ◽  
Engine Performance ◽  
Pressure Recovery ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Recovery Coefficient ◽  
Distortion Coefficient ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient

For turboprop engine, the S-shaped intake affects the engine performance and the propeller is not far in front of the inlet of the S-shaped intake, so the slipstream inevitably affects the flow field in the S-shaped intake and the engine performance. Here, an S-shaped intake with/without propeller is studied by solving Reynolds-averaged Navier-Stokes equation employed SST k-ω turbulence model. The results are presented as time-averaged results and transient results. By comparing the flow field in S-shaped intake with/without propeller, the transient results show that total pressure recovery coefficient and distortion coefficient on the AIP section vary periodically with time. The time-averaged results show that the influence of propeller slipstream on the performance of S-shaped intake is mainly circumferential interference and streamwise interference. Circumferential interference mainly affects the secondary flow in the S-shaped intake and then affects the airflow uniformity; the streamwise interference mainly affects the streamwise flow separation in the S-shaped intake and then affects the total pressure recovery. The total pressure recovery coefficient on the AIP section for the S-shaped intake with propeller is 1%-2.5% higher than that for S-shaped intake without propeller, and the total pressure distortion coefficient on the AIP section for the S-shaped intake with propeller is 1%-12% higher than that for the S-shaped intake without propeller. However, compared with the free stream flow velocity ( Ma = 0.527 ), the influence of the propeller slipstream belongs to the category of small disturbance, which is acceptable for engineering applications.

Numerical Study on the Plasma Generated by Different Discharge Modes at the Upstream of Fuel Jet in Scramjet Combustor

2013 ◽  
Vol 444-445 ◽  
pp. 1345-1349
Author(s):  
Si Yin Zhou ◽  
Wan Sheng Nie ◽  
Bo He ◽  
Xue Ke Che ◽  
Xue Min Tian
Keyword(s):  
Total Pressure ◽  
Recirculation Zone ◽  
Pressure Recovery ◽  
Flow Conditions ◽  
Recovery Coefficient ◽  
Discharge Mode ◽  
Scramjet Combustor ◽  
Fuel Jet ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient

How to enhance the combustion and reduce the total pressure loss in scramjet combustor are very critical for the practical application of hypersonic aircraft. Based on the dominant thermal mechanism of arc plasma, the plasma generated in combustor is regarded as a promising method to improve the combustion. As a result, the combustor model with transverse fuel jet and plasma generated by two discharge modes at the upstream of flameholding cavity is established and it is used to study the mechanism of fuel mixing enhancement through numerical investigation. The results show that an oblique shock wave would be formed at the upstream of the pseudo small plasma hump, and interact with the separation shock wave induced by the transverse jet. This results in the recirculation zone at the upstream of fuel jet being enlarged obviously. Besides that, under the non-reaction flow conditions, the total pressure recovery coefficient increases due to the plasma generated. However, the total pressure recovery coefficient varies apparently and the shear layer above the cavity is fluctuant when the plasma is generated by periodical discharge mode. While under the reaction flow conditions, the shear layer develops thicker and the total pressure recovery coefficient decreases. And due to the existing of plasma, the mole fraction of product water increases. But compared with the steady discharge mode, the level of water is lower and the total pressure recovery coefficient decreases more under the periodical discharge mode. Though the plasma generated by steady discharge mode shows better performance in assisting combustion and reducing the pressure loss, considering the energy saving and the use of different parameters of the periodical discharge, the same effects of enhancing the fuel mixing through enlarging the recirculation zone located at the upstream of fuel jet and promoting the mass exchange of cavity can be reached. More numerical experiments have to be done to optimize the parameters of periodical discharge plasma to receive a best improvement on the performance of scramjet combustor.

Effects of boundary-layers bleeding on unstart/restart characteristics of hypersonic inlets

2009 ◽  
Vol 113 (1143) ◽  
pp. 319-327 ◽  
Author(s):  
J. Chang ◽  
D. Yu ◽  
W. Bao ◽  
Y. Fan ◽  
Y. Shen
Keyword(s):  
Boundary Layer ◽  
Mach Number ◽  
Boundary Layers ◽  
Total Pressure ◽  
Performance Parameter ◽  
Recovery Coefficient ◽  
Hypersonic Inlet ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient ◽  
Hypersonic Inlets

Abstract A series of mixed-compression hypersonic inlets at different bleeding rates were simulated at different freestream conditions in this paper. The unstart/restart characteristics of hypersonic inlets were analysed and the reasons why the unstart/restart phenomenon is in existence is presented. The unstart/restart characteristics of hypersonic inlets at different bleeding rates were given. The effects of boundary-layer bleeding on the performance parameter (mass-captured coefficient, total-pressure recovery coefficient), starting and restarting Mach number of hypersonic inlets were discussed. In conclusion, boundary-layer bleeding can improve the performance parameter of hypersonic inlets, and can reduce the starting and restarting Mach number, and can broad the operation range of the hypersonic inlet.

Numerical analysis on the conceptual design of an air-breathing engine inlet working in mach number 3∼5.5

2021 ◽  
pp. 095441002110113
Author(s):  
Chao Huo ◽  
Zhenhua Yang ◽  
Zhengze Zhang ◽  
Peijin Liu
Keyword(s):  
Mach Number ◽  
Total Pressure ◽  
Back Pressure ◽  
Pressure Recovery ◽  
Shock Train ◽  
Recovery Coefficient ◽  
Air Breathing ◽  
Supersonic Inlet ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient

Based on the equal-intensity shock theory, this article designed a supersonic inlet working in Mach number 3.0∼5.5 with the background of an air-breathing engine. The inlet applied the four-shock train mixed compression configuration and inserted a sidewall compression at the beginning of the isolator. Through developing effective 3D RANS computations validated by current experiments, the performance of the designed inlet was identified. The designed inlet self-starts at freestream Mach number Ma∞ = 3.0 under which the total pressure recovery coefficient has dramatic increment, and the aerodynamic choking at the inlet throat no longer presents; the inlet keeps working at all studied flight states with zero angle of attack (AoA) and achieves shock-on-lip at the design point Ma∞ = 5.0. Both positive and negative AoAs can disrupt the equal-intensity shock allocations, which degrade the inlet performance. The inlet obtains maximum total pressure recovery coefficient at zero AoA. The maximum back pressure at Ma∞ = 3.0∼5.5 obtained by the inlet surpasses the requirements and keeps a certain margin. The inlet performance basically meets all the goals proposed by the engine.

Aerodynamic Design Investigation on Inlet-Exhaust System Using Super-Ellipse Method

2012 ◽  
Vol 246-247 ◽  
pp. 446-450
Author(s):  
Yue Feng Li ◽  
Qing Zhen Yang ◽  
Xue Jiao Deng
Keyword(s):  
Cross Section ◽  
Total Pressure ◽  
Exhaust System ◽  
Shape Index ◽  
Pressure Recovery ◽  
Recovery Coefficient ◽  
Thrust Coefficient ◽  
Ellipse Method ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient

Generally, the shape index n is selected in a form when design the inlet-exhaust system using traditional super-ellipse method. Unfortunately, this selection process is time-consuming and not precise enough, so the cross-section designed by super-ellipse method may get distortions easily, which influences the inner flow and the total pressure of the inlet-exhaust system greatly. Associating the shape index n with the variation pattern of the inlet-exhaust cross-section, an improved super-ellipse method is developed to design the inlet-exhaust system. This method ensures the precision and uniqueness of shape index n for any cross-section in an adaptive way. The numerical simulation results show that the S-shape inlet designed using this method has high total pressure recovery coefficient and lower distortion coefficient, the S-shaped nozzle has high total pressure recovery coefficient and thrust coefficient.

Design of S-Shaped Submerged Inlet

2011 ◽  
Vol 291-294 ◽  
pp. 349-354
Author(s):  
Guang Lin He ◽  
Xiao Lin Li
Keyword(s):  
Cross Section ◽  
Total Pressure ◽  
Aerodynamic Performance ◽  
New Method ◽  
Pressure Recovery ◽  
Recovery Coefficient ◽  
Distortion Coefficient ◽  
Total Pressure Recovery ◽  
The Cross ◽  
Pressure Recovery Coefficient

The influence of centerline and the cross-section variation to aerodynamic performance of the inlet was researched in a wider range. A new method of measuring the total pressure recovery coefficient and total pressure distortion coefficient of the inlet was proposed. Based on the loitering aircraft, a s-shaped inlet was designed to meet the needs of stable flight of loitering aircraft, whose total pressure recovery coefficient is 93.2% and total pressure distortion coefficient is 1.2%.

Flow Development Through An S-Shaped Diffusing Duct

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Jinfang Teng ◽  
Junda Feng ◽  
Dongrun Wu ◽  
Pan He ◽  
Mingmin Zhu
Keyword(s):  
Total Pressure ◽  
Internal Flow ◽  
Adverse Pressure Gradient ◽  
Reynolds Stress Model ◽  
Pressure Recovery ◽  
Experimental Result ◽  
Recovery Coefficient ◽  
Flow Development ◽  
Total Pressure Recovery ◽  
Pressure Recovery Coefficient

AbstractThis paper focuses on the internal flow development of an S-shaped diffusing duct. Based on the experimental result of total pressure recovery coefficient, the Reynolds stress model (RSM) was selected as a suitable turbulence model for the present study. The numerical results show that 6.2 times the area ratio of the exit to inlet and the aggressive deflection at the first bend of the lower wall lead to strong adverse pressure gradient and very large flow separation, and create a pair of counter-rotating vortices along streamwise direction. The duct diffuser efficiency is 72.37 %. The area-averaged total pressure recovery coefficient at the exit of the duct is 0.9814, and the synthesis distortion index DC (60) is 0.7081.

Insight in the Performance of Scramjet Combustor Based on Orthogonal Experimental Design

2013 ◽  
Vol 705 ◽  
pp. 463-467
Author(s):  
Wen Qiang Cheng ◽  
Jing Yuan Liu ◽  
Rakesh Shrestha
Keyword(s):  
Total Pressure ◽  
Combustion Efficiency ◽  
Pressure Recovery ◽  
Orthogonal Experimental Design ◽  
Recovery Coefficient ◽  
Factors Affecting ◽  
Scramjet Combustor ◽  
Total Pressure Recovery ◽  
Main Factors ◽  
Pressure Recovery Coefficient

A numerical insight was accomplished to optimize the scramjet combustor configuration based on orthogonal experimental design. Parametric modeling of combustor configurations was performed by the orthogonal array with 13 factors at 3 levels. Numerical simulations were proceeded by k-ε standard turbulence model and eddy-dissipation model in the combustion process. The performance indexes of combustion efficiency, total pressure recovery coefficient and thrust gain coefficient were evaluated. Detailed comparison with the effect of the factors on the performance was also carried out to demonstrate the main factors and determine the optimal configuration. The analysis of the extreme differences of the factors indicates that the main factors affecting combustion efficiency were the length of the wedge, the length depth ratio of the cavity, the depth of the cavity, and the length of the expanding section; The main factors affecting total pressure recovery coefficient are the angle of the primary combustor, the length of the expanding section, and the thickness of the strut; The main factors affecting thrust gain coefficient are the thickness of the strut, the length of the expanding section, and the angle of the secondary combustor. Validation of the optimal configuration is then confirmed that its performance is higher than the rest of the configurations, with the combustion efficiency of 0.915 and the total pressure recovery coefficient of 0.486, which are 31.5% and 65.9% higher than the experimental results, respectively.

Effect of the turning angle on the flow and performance characteristics of long S-shaped circular diffusers

2003 ◽  
Vol 217 (1) ◽  
pp. 29-41 ◽  
Author(s):  
R B Anand ◽  
L Rai ◽  
S N Singh
Keyword(s):  
Total Pressure ◽  
Static Pressure ◽  
Area Ratio ◽  
Secondary Flows ◽  
Performance Characteristics ◽  
Pressure Recovery ◽  
Recovery Coefficient ◽  
Turning Angle ◽  
And Performance ◽  
Pressure Recovery Coefficient

The effect of the turning angle on the flow and performance characteristics of long S-shaped circular diffusers (length-inlet diameter ratio, L/Di = 11:4) having an area ratio of 1.9 and centre-line length of 600 mm has been established. The experiments are carried out for three S-shaped circular diffusers having angles of turn of 15°/15°, 22.5°/22.5° and 30°/30°. Velocity, static pressure and total pressure distributions at different planes along the length of the diffusers are measured using a five-hole impact probe. The turbulence intensity distribution at the same planes is also measured using a normal hot-wire probe. The static pressure recovery coefficients for 15°/15°, 22.5°/22.5° and 30°/30° diffusers are evaluated as 0.45, 0.40 and 0.35 respectively, whereas the ideal static pressure recovery coefficient is 0.72. The low performance is attributed to the generation of secondary flows due to geometrical curvature and additional losses as a result of the high surface roughness (~0.5 mm) of the diffusers. The pressure recovery coefficient of these circular test diffusers is comparatively lower than that of an S-shaped rectangular diffuser of nearly the same area ratio, even with a larger turning angle (90°/90°), i.e. 0.53. The total pressure loss coefficient for all the diffusers is nearly the same and seems to be independent of the angle of turn. The flow distribution is more uniform at the exit for the higher angle of turn diffusers.

Influence of Area Distribution With Fixed Trajectory on Serpentine Intake Duct Performance

2012 ◽  
Author(s):  
Ritesh Gaur ◽  
Vimala Narayanan ◽  
S. Kishore Kumar
Keyword(s):  
Total Pressure ◽  
Pressure Recovery ◽  
Maximum Pressure ◽  
Recovery Coefficient ◽  
Cross Sectional ◽  
Fixed Boundary ◽  
Area Distribution ◽  
Pressure Recovery Factor ◽  
Minimum Distortion ◽  
Pressure Recovery Coefficient

Performance of intake duct with fixed inlet trajectory and different area distributions have been analyzed using a commercial CFD (Computational Fluid Dynamics) software. The performance have been evaluated for fixed boundary conditions. The area distributions studied are defined by varying cross sectional area at different locations of intake duct by keeping the inlet and exit area same. The performance of the intake ducts are studied in terms of the pressure recovery coefficient, total pressure loss, pressure recovery factor and distortion coefficient in the present work. The motion caused by the change in centerline curvature is analyzed. The objective of the work is to derive a shape of the duct with minimum distortion of the flow and maximum pressure recovery.

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