The flow field in a typical inward-turning inlet was visualized using the Planar Laser Scattering(PLS)method in a shock tunnel with a nominal Mach number of 6.The opaque inlet,which is truncated at a series of section...The flow field in a typical inward-turning inlet was visualized using the Planar Laser Scattering(PLS)method in a shock tunnel with a nominal Mach number of 6.The opaque inlet,which is truncated at a series of sections,and the following transparent isolator,are combined to enable the optical access at different streamwise locations.The sequential PLS images provide a tomography-like flow visualization,which confirm the existence of streamwise Counter-rotating Vortex Pairs(CVPs)in both external and internal flow field of the inlet.Generation mechanisms of these CVPs are unraveled with the help of a numerical simulation,among which the cowl notch plays an important role in the generation of surface trailing CVPs along the centerline of the cowl.Moreover,the cowl shock sweeps the internal boundary layer towards the body side,which ultimately accumulates low-momentum flow on the body side in forms of a large CVP propagating downstream through the isolator.The CVPs formed in the shape-transition are responsible for the nonuniform flow field of the inward-turning inlet.This study indicates that the V-shaped cowl notch affects the downstream flow significantly and,therefore,should be examined thoroughly in practical applications.展开更多
In the design of a hypersonic inward-turning inlet by applying the traditional basic flowfield, a reflected shock-wave is formed in the isolator due to the continuous reflection of the cowlreflected shock wave in the ...In the design of a hypersonic inward-turning inlet by applying the traditional basic flowfield, a reflected shock-wave is formed in the isolator due to the continuous reflection of the cowlreflected shock wave in the basic flow-field, which interacts with the boundary layer to produce a considerable influence on the performance of the inlet. Here, a basic flow-field design method that can control the velocity direction at the throat section is developed, and numerical simulations are conducted to demonstrate the effectiveness of this method. The method presented in this paper can achieve the absorption of the reflected waves at the shoulder of the basic flow-field by adjusting the variation law of the center radius in the basic flow-field, and a smooth transition between the compression surface and the isolator can also be produced. The Mach number and total pressure recovery coefficient of the inlet designed according to this method are 3.00 and 0.657, respectively, at design point(the incoming flow Mach number Ma1= 6.0). The results show that with this method, the inlet can efficiently weaken both the reflection of the shock wave and the interaction between the boundary layer and the reflected shock waves, which improves the aerodynamic performance of the inlet.展开更多
In this work, a novel airframe/propulsion integration design method of the wing-body configuration for hypersonic cruise aircraft is proposed, where the configuration is integrated with inward-turning inlets. With the...In this work, a novel airframe/propulsion integration design method of the wing-body configuration for hypersonic cruise aircraft is proposed, where the configuration is integrated with inward-turning inlets. With the help of this method, the major design concern of balancing the aerodynamic performance against the requirements for efficient propulsion can be well addressed. A novel geometric parametrically modelling method based on a combination of patched class and shape transition（CST） and COONs surface is proposed to represent the configuration, especially a complex configuration with an irregular inlet lip shape. The modelling method enlarges the design space of components on the premise of guaranteeing the configuration integrity via special constraints imposed on the interface across adjacent surfaces. A basic flow inside a cone shaped by a dual-inflection-point generatrix is optimized to generate the inward-turning inlet with improvements of both compression efficiency and flow uniformity. The performance improvement mechanism of this basic flow is the compression velocity variation induced by the variation of the generatrix slope along the flow path. At the design point, numerical simulation results show that the lift-to-drag ratio of the configuration is as high as 5.2 and the inlet works well with a high level of compression efficiency and flow uniformity. The design result also has a good performance on off-design conditions. The achievement of all the design targets turns out that the integration design method proposed in this paper is efficient and practical.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11772325,11872356 and 11621202)。
文摘The flow field in a typical inward-turning inlet was visualized using the Planar Laser Scattering(PLS)method in a shock tunnel with a nominal Mach number of 6.The opaque inlet,which is truncated at a series of sections,and the following transparent isolator,are combined to enable the optical access at different streamwise locations.The sequential PLS images provide a tomography-like flow visualization,which confirm the existence of streamwise Counter-rotating Vortex Pairs(CVPs)in both external and internal flow field of the inlet.Generation mechanisms of these CVPs are unraveled with the help of a numerical simulation,among which the cowl notch plays an important role in the generation of surface trailing CVPs along the centerline of the cowl.Moreover,the cowl shock sweeps the internal boundary layer towards the body side,which ultimately accumulates low-momentum flow on the body side in forms of a large CVP propagating downstream through the isolator.The CVPs formed in the shape-transition are responsible for the nonuniform flow field of the inward-turning inlet.This study indicates that the V-shaped cowl notch affects the downstream flow significantly and,therefore,should be examined thoroughly in practical applications.
基金supported by the National Natural Science Foundation of China (Nos. 11702229, 11602207 and 91641103)
文摘In the design of a hypersonic inward-turning inlet by applying the traditional basic flowfield, a reflected shock-wave is formed in the isolator due to the continuous reflection of the cowlreflected shock wave in the basic flow-field, which interacts with the boundary layer to produce a considerable influence on the performance of the inlet. Here, a basic flow-field design method that can control the velocity direction at the throat section is developed, and numerical simulations are conducted to demonstrate the effectiveness of this method. The method presented in this paper can achieve the absorption of the reflected waves at the shoulder of the basic flow-field by adjusting the variation law of the center radius in the basic flow-field, and a smooth transition between the compression surface and the isolator can also be produced. The Mach number and total pressure recovery coefficient of the inlet designed according to this method are 3.00 and 0.657, respectively, at design point(the incoming flow Mach number Ma1= 6.0). The results show that with this method, the inlet can efficiently weaken both the reflection of the shock wave and the interaction between the boundary layer and the reflected shock waves, which improves the aerodynamic performance of the inlet.
基金supported by the ‘‘111" Project of China (No. B17037)
文摘In this work, a novel airframe/propulsion integration design method of the wing-body configuration for hypersonic cruise aircraft is proposed, where the configuration is integrated with inward-turning inlets. With the help of this method, the major design concern of balancing the aerodynamic performance against the requirements for efficient propulsion can be well addressed. A novel geometric parametrically modelling method based on a combination of patched class and shape transition（CST） and COONs surface is proposed to represent the configuration, especially a complex configuration with an irregular inlet lip shape. The modelling method enlarges the design space of components on the premise of guaranteeing the configuration integrity via special constraints imposed on the interface across adjacent surfaces. A basic flow inside a cone shaped by a dual-inflection-point generatrix is optimized to generate the inward-turning inlet with improvements of both compression efficiency and flow uniformity. The performance improvement mechanism of this basic flow is the compression velocity variation induced by the variation of the generatrix slope along the flow path. At the design point, numerical simulation results show that the lift-to-drag ratio of the configuration is as high as 5.2 and the inlet works well with a high level of compression efficiency and flow uniformity. The design result also has a good performance on off-design conditions. The achievement of all the design targets turns out that the integration design method proposed in this paper is efficient and practical.
