Supersonic Air Intake Research Articles

Influence of Plasma on the Supersonic Air-intake Buzz

Influence of Plasma on the Supersonic Air-intake Buzz

Characterization of a supersonic mixed-compression air intake at high back pressures

Characterization of a supersonic mixed-compression air intake at high back pressures

Numerical Study of the Features of the Propagation of Acoustic Disturbances in an Unregulated Supersonic Air Intake

Numerical Study of the Features of the Propagation of Acoustic Disturbances in an Unregulated Supersonic Air Intake

Study of the Vortex-Resolving Method of the Throttling Effect on Pressure Pulsation Spectra in a Paired Supersonic Air Intake

Study of the Vortex-Resolving Method of the Throttling Effect on Pressure Pulsation Spectra in a Paired Supersonic Air Intake

Starting Characteristics of Curved Compression Ramp Air Intakes with Overboard Spillage

An analytical framework is presented here for estimating the limiting area contraction for a family of curved compression ramp (CCR) supersonic air intakes with self-starting capability via overboard spillage. Flow compression in CCR intakes occurs through a combination of a curved ramp shock wave and a series of compression waves. In general, such a combination offers the best features of the canonical air intake families. That is, pressure recovery in CCR intakes is better than simple ramp (planar ramp) air intakes, and pressure ratios in CCR intakes are better than Prandtl–Mayer air intakes. A modified Kantrowitz criterion for startability is proposed to accommodate the nonuniform Mach number distribution in the cross-stream direction at the intake throat that is inevitably realized in CCR air intakes. The starting characteristics of different design configurations that fall within the family of CCR air intakes are analyzed, and a comparison is made with planar ramp and Prandtl–Meyer intakes. Inviscid flow numerical experiments of intake starting were carried out to successfully verify the starting characteristics predicted by the analytical model. The analytical framework presented here can be employed as a general tool for optimizing air intake design based on startability, efficiency, and other performance considerations.

Study of vortex-resolving method of throttling effect on pressure pulsation spectra in a paired supersonic air intake

С помощью вихреразрешающего RANS/ILES метода исследовано течение в спаренном модельном сверхзвуковом воздухозаборнике (ВЗ) смешанного сжатия с системой слива пограничного слоя. Проанализировано влияние типа системы слива пограничного слоя и дросселирования соседних ВЗ на особенности течения, уровень и спектры пульсаций давления в каждом из ВЗ. Рассмотрены варианты с одинаковым и различным дросселированием в каждом из ВЗ, общей и раздельной для соседних ВЗ системой слива. Дано краткое описание метода расчета и граничных условий. Представлены уровни OASPL в ВЗ в зависимости от степени дросселирования. Выявлено влияние дросселирования одного из ВЗ на течение и особенности 1/3-октавных спектров пульсаций давления в соседнем ВЗ.

Starting of a scramjet air intake

The starting of a supersonic air-intake at the design Mach number depends on the internal blockage due to flame-holder struts in the combustor. In the present work, the starting of a two-dimensional supersonic air-intake for scramjet operation was verified experimentally on an isolated full-scale truncated model. The first ramp of the supersonic air-intake was truncated and simulated from downstream of the second ramp where the local Mach number was 3.7. The flight mission dictated the opening time of the cowl plate to be fixed as 200 mS. The maximum blockage of struts which allows the intake to start was determined by varying the blockage ratio in the range of 20% to 30%. The results indicate that the intake starts when the blockage ratio was 20%, but unstarts for 25% and 30%. In the unstart condition, discrete frequencies of 45 Hz and 60 Hz occurred and pressure fluctuations in the intake showed limit cycle oscillations. A detailed analysis of unsteady pressure fluctuations confirms that the buzz could be modeled as a Van Der Pol oscillator with nonlinear damping.

Flow Field Investigation of a Rectangular Supersonic Air-Intake With Cowl Bending

Experimental and computational studies are made on a rectangular mixed compression air-intake designed for Mach 2.2 to study the effect of cowl bending. Flow field details inside the intake have been captured using schlieren flow visualisation and measurement of static and total pressures. Three dimensional simulations have been made with RANS solver adopting k-ω turbulence model using FLUENT. Studies show that the configuration indicate unstart without any cowl bending whereas startup is observed with adoption of small cowl bend. In addition, improvement in quality of flow inside the intake has been observed. In general, agreements between experimental and computational results are good. Studies have been also made at different back pressures. Provision of a small cowl bending could lead to better performance of intake.

One-Dimensional Model for Calculation of Flow Parameters in a Supersonic Air Intake

One-Dimensional Model for Calculation of Flow Parameters in a Supersonic Air Intake

Numerical simulation of starting conditions for a supersonic air intake with a rectangular duct and partial release of the captured air stream through longitudinal slots

Numerical simulation of starting conditions for a supersonic air intake with a rectangular duct and partial release of the captured air stream through longitudinal slots

Analysis of the Influence of Incoming Flow Turbulence on the Flow in a Supersonic Air Intake by the RANS/ILES Method. Estimation of Dissipative Properties of the Difference Scheme by an Example of Modeling the Decay of Homogeneous Isotropic Turbulence in the ILES

Analysis of the Influence of Incoming Flow Turbulence on the Flow in a Supersonic Air Intake by the RANS/ILES Method. Estimation of Dissipative Properties of the Difference Scheme by an Example of Modeling the Decay of Homogeneous Isotropic Turbulence in the ILES

Studying the Effect of Throttling by the RANS/ILES Method on Pressure Pulsations in a Multiple-Modules Supersonic Air Intake

Studying the Effect of Throttling by the RANS/ILES Method on Pressure Pulsations in a Multiple-Modules Supersonic Air Intake

Effects of boundary-layer bleed parameters on supersonic intake buzz

Extensive wind tunnel tests were conducted to study effects of the location, entrance slant angle, entrance width, and type (slot or porous) of boundary layer bleed on the buzz phenomenon in a supersonic air intake. The intake was a mixed-compression axisymmetric intake for the design Mach number of 2.0 that was studied at zero degrees angle of attack at three free stream Mach numbers of 1.8, 2.0, and 2.2 through shadowgraph visualization system and pressure recordings. For every free stream Mach number and bleed geometry, eight different back pressures were examined. Results showed that the bleed can significantly postpone the buzz onset and increase the stability range of the intake. The bleed location was the most effective parameter among the examined parameters of the bleed system. According to the results, the bleed restricts the domain of shock oscillations to downstream of the bleed entrance and consequently, it increases the frequency of buzz as compared with the no-bleed case. In addition, the slot bleed is more effective in stabilizing the intake flow field than the porous bleed.

Parametric Study on Influence of an Array of Air Jets on the Performance of Supersonic Air Intake by Varying the Jet Injection and Back Pressure

A numerical study on the performance parameters of supersonic mixed compression air intake has been carried out at a design Mach number of 2.2 with and without air jets at various back-pressure ratios using a commercially available software, Ansys 2019. The k-omega turbulence model was selected to capture the viscous effects. The injection pressure and the gap between the air jets were also varied to see the effect on flow field inside the air intake. The location of the air jets was kept fixed in the longitudinal direction and the position of the normal shock was varied by changing the back pressure. Mass flow ratio, flow distortion, total pressure recovery, and skin friction coefficient were chosen to measure the performance of air intake. The results suggest that a proper combination of the number of air jets and their injection pressure can improve the performance and flow field of the supersonic air intake. Deployment of four air jets with an injection pressure ratio of 4 has shown the best performance for all back-pressure cases studied.

Control of shock‐induced separation inside air intake by vortex generators

AbstractThe present investigation is aimed towards the effect of passive methods on the performance of supersonic air intake along with the control of shock wave boundary layer interaction at various engine operating conditions. A computational study has been carried out in this regard using the commercially available software Ansys Fluent. The k–ω turbulence model has been selected for the present investigation. All the simulations have been carried out at a design Mach number of 2.2. The Independent effect of the air‐jet vortex generator (AJVG), tapered micro ramp vortex generator (MRVG), and the combined effect of AJVG with MRVG on the shock wave boundary layer interaction have been investigated. Detailed comparative studies of all controlled cases with uncontrolled cases show significant improvement in the flow field inside the air intake and improved performance. The shock train is also captured for all the cases along with shock wave boundary layer interaction at various operating conditions. The movement of the normal shocks is seen as the backpressure increases. All the essential performance parameters related to air intake have been examined in detail. The hybrid type of control showed better performance.

INTEGRATED APPROACH TO GAS-DYNAMIC DESIGNING OF SUPERSONIC AIR INTAKES OF AIRCRAFT

The analytical and experimental studies of the aircraft’s supersonic air intakes have been carried out. An integrated approach to the gas-dynamic designing of aircraft’s supersonic air intakes that eliminates the scale effect problem of a wind tunnel with a small-sized testing area is proposed. The designing approach accelerates the development process and reduces the resource intensity due to the rational distribution of tasks between numerical and physical experiments. The results of the unique tests of the scaled ramjet’s air intake physical model in the supersonic wind tunnel are presented.

Numerical Study of Supersonic Mixed Compression Air Intake With an Array of Air Jets

Abstract Computational study of flow physics inside the mixed compression air intake has been carried out with and without air jets (AJs) at design Mach number of 2.2. Reynolds-averaged Navier–Stokes (RANS) equations were solved with k–ω turbulence model by using commercially available software ansys. The scope of this research is to improve the flow field inside the air intake and efficiency of supersonic air intake by implementing AJs on the ramp surface. An array of AJs containing two, four, and five AJ holes, respectively, of 1 mm each has been made on the ramp surface perpendicular to the flow with equal spacing between them. The injection pressure through AJ has been kept constant for all the cases. Flow distortion (FD) and total pressure recovery (TPR) were selected to measure the performance of air intake. All the simulations have been performed at a back-pressure ratio of 6. The results obtained suggest that implementation of proper spacing between AJs can improve the performance of air intake due to the mixing of vortices generated by AJs with freestream flow. It is revealed that an array of AJs containing four holes on ramp surface works best and helps in controlling the shock-induced separation.

Оценка применимости различных моделей турбулентности для исследования высокоскоростных течений в воздухозаборных устройствах

The study focuses on the problem of optimization of the shock wave system which implements the maximum total pressure. Relying on the problem solution, we selected the configuration of a supersonic air intake of external compression and carried out numerical simulation of the flow in the air intake in flight conditions with the free-stream Mach number equal to 7.5 using the ideal gas model for calculations. The system of Favre-averaged Navier — Stokes equations was supplemented by one of the turbulence models: Spalart — Allmaras model, k–ε, k–ω, and γ–Reθ. The paper deals with both two-dimensional and three-dimensional configurations of the air input and studies the influence of angles of attack, wall temperature, and free-stream Mach number on the flow characteristics. Within the research, we determined the ranges of Mach numbers corresponding to the starting mode of the air intake and described the hysteresis of characteristics at the transition of the air intake to the start-up mode for various turbulence models.

Flow Field Study of Mixed Compression Supersonic Air Intake with Cowl Ventilation

The present investigation is focused on the effect of cowl porosity on the performance of supersonic mixed compression air intake. Four different cases (namely 4.4 %, 5 %, 5.5 % and 7.2% of total cowl area) of cowl porosity at three contraction ratios of air intake have been studied. The pattern of the cowl porosity (Square shape) is chosen symmetrically along the span in the longitudinal direction from the cowl tip. Commercially available software Ansys is used in the computational studies to solve the RANS equations with the k-ω STD turbulence model. Various performance parameters of supersonic air intake are obtained and discussed. Excess amount of flow spillage appears near the cowl tip, which is responsible for the standing strong bow shock wave just before the throat for the uncontrolled case (Clean Model). The minimum energy losses and starting behavior of supersonic air intake are captured at 7.2 % cowl porosity for the contraction ratio of 1.25, which reveals the overall improvement in the flow physics and performance parameters. An increase of 32.73 % in the total pressure recovery is observed for 7.2 % cowl porosity at design contraction ratio of 1.25. All the simulations are performed at three contraction ratios of 1.22, 1.25 & 1.31.

Effect of air jet with injection pressure on the performance of mixed compression air intake

A computational study on the performance of mixed compression supersonic air intake has been carried out with and without air jet at various operating conditions. Commercially available software ANSYS was used and K-ω SST turbulence model was selected to capture the turbulent flow inside the air intake. All the simulations were simulated at a design Mach number of 2.2. Two Air jet of 1 mm diameter each and perpendicular to the local ramp surface have been placed in longitudinal direction at 0.47 times the total length of the air intake. Effect of variation of injection pressure on the flow field of air intake has been studied. Injection pressure has been varied with respect to the free stream pressure. Four different cases of injection pressure have been investigated. Three different positions (1.far away before the air jet, 2. immediately after the air jet and 3. far away behind the air jet) of normal shock were simulated to study the effect of air jet by varying the back pressure of the supersonic air intake. Significant reduction in the flow separation due the normal shock wave was noticed for all the cases of injection pressure, which further helps in improving the performance of the supersonic air intake. Important performance parameters such as flow distortion, mass flow ratio and total pressure recovery were calculated to measure the efficacy of supersonic air intake with air jet at various operating conditions.