Flow characteristics of hypersonic inlets with different cowl-lip blunting methods

Abstract

Under hypersonic flight conditions, the sharp cowl-lip leading edges have to be blunted because of the severe aerodynamic heating. This paper proposes four cowl-lip blunting methods and studies the corresponding flow characteristics and performances of the generic hypersonic inlets by numerical simulation under the design conditions of a flight Mach number of 6 and an altitude of 26 km. The results show that the local shock interference patterns in the vicinity of the blunted cowl-lips have a substantial influence on the flow characteristics of the hypersonic inlets even though the blunting radius is very small, which contribute to a pronounced degradation of the inlet performance. The Equal Length blunting Manner (ELM) is the most optimal in that a nearly even reflection of the ramp shock produces an approximately straight and weak cowl reflection shock. The minimal total pressure loss, the lowest cowl drag, maximum mass-capture and the minimal aeroheating are achieved for the hypersonic inlet. For the other blunting manners, the ramp shock cannot reflect evenly and produces more curved cowl reflection shock. The Type V shock interference pattern occurs for the Cross Section Cutting blunting Manner (CSCM) and the strongest cowl reflection shock gives rise to the largest flow loss and drag. The cowl-lip blunted by the other two blunting manners is subjected to the shock interference pattern that transits with an increase in the blunting radius. Accordingly, the peak heat flux does not fall monotonously with the blunting radius increasing. Moreover, the cowl-lip surface suffers from severe aerothermal load when the shear layer or the supersonic jet impinges on the wall.

Alterations of Cowl Lip for the Improvement of Supersonic-Intake Performance

“…Studies focusing on the suppression of SWBLI induced separation bubble were also reported in the past. Blunting the cowl leading edge has been put forth as an effective means of separation reduction by Lu et al (2014). In this numerical study, four different cowl-lip blunting methods were investigated to understand the flow characteristics of hypersonic intake under the design conditions corresponding 26 km altitude and Mach number of 6.…”

Aerothermal characteristics of bleed slot in hypersonic flows

“…In addition, the multi-grid and dual time-step methods are employed to accelerate convergence. Our previous studies [36,37] have verified that the adopted numerical algorithm is very credible and can efficiently resolve high Mach number flows and aerodynamic heating.…”

“…And for  = 90° it is 0.0311 at SoUSC, 0.0240 at SoSOC while 0.0095 at SoDSC. According to the research on shock interference [37,40], the Stanton number at the stagnation point may rise dramatically at SoDSC, even higher than that at SoSOC or SoUSC, once the type IV shock interference triggers strong supersonic jet for an appropriate location of incident shock intersecting point rela-tive to the barrier shock. Figure 13 plots the heat flux distribution on the plate downstream of the slot for different slot locations relative to shock impingement point.…”

Role of wall temperature on shock train in a rectangular isolator

“…Because static pressure keeps constant for different wall temperatures, the density increases considerably with wall temperature from the state P=ρRT. Thus the effect of wall cooling is to reduce the boundary layer thickness , as reported in the literature [28]. The fullness of velocity distributions in the boundary layer can be denoted by u ∞ /.…”