scholarly journals Direct-Connect Test of Solid Scramjet with Symmetrical Structure

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5589
Author(s):  
Pengnian Yang ◽  
Zhixun Xia ◽  
Likun Ma ◽  
Binbin Chen ◽  
Yunchao Feng ◽  
...  
Keyword(s):  
Total Pressure ◽  
Solid Propellant ◽  
Ignition Delay Time ◽  
Specific Impulse ◽  
Combustion Efficiency ◽  
Gas Generator ◽  
Recovery Coefficient ◽  
Symmetrical Structure ◽  
Cavity Configuration ◽  
Pressure Recovery Coefficient

The solid scramjet has become one of the most promising engine types. In this paper, we report the first direct-connect test of a solid scramjet with symmetrical structure, carried out using boron-based fuel-rich solid propellant as fuel. During the test, which simulated a flight environment at Mach 5.6 and 25 km, the performance of the solid scramjet was obtained by measuring the pressure, thrust, and mass flow. The results show that, due to the change in the combustion area of the propellant and the deposition of the throat in the gas generator during the test, the equivalence ratio gradually increased from 0.54 to 0.63. In a solid scramjet, it is possible to obtain a symmetrical distribution of the flow field within the combustor. Moreover, in a multi-cavity combustor, the combustion state expands from the cavity to the center of the flow channel. The performance of the solid scramjet increased during the test, reaching a combustion efficiency of about 42%, a total pressure recovery coefficient of 0.35, and a thrust gain specific impulse of about 418 s. The solid scramjet with symmetrical structure is feasible. The cavity configuration adopted in this paper can reduce the ignition delay time of fuel-rich gas and improve the combustion efficiency of gas-phase combustible components. The shock trains in the isolator are conducive to the recovery of the total pressure. The performance of the solid scramjet is limited by the low combustion efficiency of the particles.

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.

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.

scholarly journals Numerical Investigation of the Influence of Injection Scheme on the Ethylene Supersonic Combustion

2014 ◽  
Vol 6 ◽  
pp. 124204 ◽  
Author(s):  
Hao Ouyang ◽  
Weidong Liu ◽  
Mingbo Sun
Keyword(s):  
Heat Release ◽  
Separation Zone ◽  
Injection Pressure ◽  
Combustion Efficiency ◽  
Supersonic Combustion ◽  
Recovery Coefficient ◽  
Starting Point ◽  
Combustion Flow ◽  
Inlet Unstart ◽  
Pressure Recovery Coefficient

Ethylene supersonic combustion flow field in different injection schemes was studied numerically in the flight Mach 4. The results show that injection pressure has significant influence on the location of the separation zone and the heat release region, but the starting point of the separation region was mostly influenced by the heat release rather than by the injection pressure; the combustion efficiency of the injection schemes including two injection points is higher than that of three injection points, while the total pressure recovery coefficient of the former injection schemes is lower than the latter; excessive ethylene injected in upstream will lead to the change of free-stream flow conditions, which behaves as the inlet unstart in practical application; more ethylene could be injected in downstream to avoid the problem; on the condition of avoiding thermal choke in isolator, it is more advantageous that injection points were arranged more closely to the starting point of separation zone in upside and to the front of the cavity in downside.

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.

Turbocharged Solid Propellant Ramjet for Tactical Missile

2012 ◽  
Vol 152-154 ◽  
pp. 204-209 ◽  
Author(s):  
Sa Yang ◽  
Guo Qiang He ◽  
Yang Liu ◽  
Jiang Li
Keyword(s):  
Solid Propellant ◽  
Specific Impulse ◽  
Design Parameters ◽  
Gas Generator ◽  
Specific Thrust ◽  
Independent Design ◽  
Performance Calculation

Turbocharged solid propellant ramjet (TSPR) is the combination of solid propellant gas generator air turbo ramjet (ATR)with solid ramjet, is cycle of augmented ATR, the parametric performance calculation were carried out for TSPR, The effects of independent design parameters including parameters of compressor and turbine and propellants were studied and the preferred compressor, turbine and propellants were obtained for TSPR; The operation envelop of TSPR and ATR were obtain under the preferred component limitation, the results shows that TSPR offers wide speed-altitude operation envelope, high specific thrust, high specific impulse, it is combining the advantages of the ATR and solid ramjet, and suitable for tactical missiles application meets potential requirements for boosting and cruising.

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.

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.

scholarly journals Numerical Study on Internal flow Field Dynamic Performance of Scramjet

2019 ◽  
Vol 288 ◽  
pp. 02009
Author(s):  
Feng Gao ◽  
Jie Zhao ◽  
Feng Li Chen
Keyword(s):  
Total Pressure ◽  
Pressure Pulsation ◽  
Dynamic Performance ◽  
Great Influence ◽  
Back Pressure ◽  
Flow Coefficient ◽  
Intake Port ◽  
Recovery Coefficient ◽  
And Performance ◽  
Pressure Recovery Coefficient

The pressure pulsation caused by the combustion of the combustion chamber of the scramjet engine has a great influence on the flow and performance of the inlet. Although the isolation section prevents the propagation of this pressure pulsation, the pressure pulsation still flows to the inlet flow field. And performance has an adverse effect. In this paper, a method for calculating the dynamic performance parameters of the inlet is discussed. The influence of the pulsating pressure of the combustion chamber on the performance of the inlet is preliminarily studied. The influence law of different forms of back pressure pulsation on the flow coefficient and the total pressure recovery coefficient is obtained. Different back pressure pulsation forms have a great influence on the flow coefficient. The faster the response, the more obvious the change of the flow coefficient. The larger the reduction, the more likely the inlet channel will not start. Different back pressure pulsations have little effect on the total pressure recovery coefficient. In the design of the intake port, the influence of the back pressure pulsation on the performance of the intake port should be fully taken into consideration, and measures should be taken to prevent the performance of the intake port from being affected by the back pressure pulsation.

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