Empirical Equation for Self-starting Limit of Supersonic Inlets

Analysis of a Three-Dimensional, High Pressure Ratio Scramjet Inlet with Variable Internal Contraction

“…When the flow starts, the static pressure drops and total pressure rises sharply, as illustrated in Figure 6 (left image). The critical internal contraction of I crit = 1.98 fits very well with results from other investigations [40]. The figure also shows the comparison of two different cowl velocities, in order to ensure that the process is not influenced by hysteresis effects.…”

“…2, the intake flow does not start spontaneously at one point, but at first, at a higher internal contraction ratio of about I = 2.2 (corresponding to a lip position of x lip = 345 mm), only partially builds up, but only at an internal contraction ratio lower than in the case of condition 1, the flow is fully established, at around x lip = 366 mm or I crit,2 = 1.9. The starting limits for both conditions are displayed in Figure 7 in relation to the Kantrowitz limit [39] and an empirical relation found by Sun [40], which correlates data from various kinds of investigations on 3D-inlets.…”

Experimental Investigation of the Starting Behavior of a three-dimensional SCRamjet Intake with a Movable Cowl and Exchangeable Cowl Geometry at Different Mach Numbers

“…12 Furthermore, the effect of delayed intake starting due to lower free stream Mach number can be explained: a reduced free stream Mach number leads to a reduced Mach number at the cowl closure position as well. Moving to the left in the Kantrowitz diagram leads to a decreased internal contraction ratio for intake starting.…”

The Phenomena of Sudden Change in Hypersonic Inlets Self-Starting Capability

“…Kantrowitz proposed a theoretical model for supersonic inlet restart with assumption of a normal shock wave in front of the internal contraction and quasi-steady one-dimensional isentropic internal flow with sonic condition at the inlet throat [1,2] . But unfortunately the restart flow pattern for hypersonic inlet is much different from the assumption and there is a strong shock associated with a large scale boundary layer separation [3] . Many experiments have verified that the inlet can restart at internal contraction ratio beyond Kantrowitz limit [3][4][5] .…”

“…But unfortunately the restart flow pattern for hypersonic inlet is much different from the assumption and there is a strong shock associated with a large scale boundary layer separation [3] . Many experiments have verified that the inlet can restart at internal contraction ratio beyond Kantrowitz limit [3][4][5] .…”