Thrust shock vector control of an axisymmetric conical supersonic nozzle via secondary transverse gas injection

Abstract

International audienceTransverse secondary gas injection into the supersonic flow of an axisymmetric convergent-divergent nozzle is investigated to describe the effects of the fluidic thrust vectoring within the framework of a small satellite launcher. Cold-flow dry-air experiments are performed in a supersonic wind tunnel using two identical supersonic conical nozzles with the different transverse injection port positions. The complex three-dimensional flow field generated by the supersonic cross-flows in these test nozzles was examined. Valuable experimental data were confronted and compared with the results obtained from the numerical simulations. Different nozzle models are numerically simulated under experimental conditions and then further investigated to determine which parameters significantly affect thrust vectoring. Effects which characterize the nozzle and thrust vectoring performances are established. The results indicate that with moderate secondary to primary mass flow rate ratios, ranging around 5 %, it is possible to achieve pertinent vector side forces. It is also revealed that injector positioning and geometry have a strong effect on the shock vector control system and nozzle performances

Experimental and Numerical Study of Thrust-Vectoring Effects by Transverse Gas Injection into a Propulsive Axisymmetric C-D Nozzle

“…Among different types of FTV as skewing of the throat sonic line or Coanda's effect counter and co flow injection, direct transverse injection into divergent portion of the C-D nozzle is selected as a straightforward and efficient technique for diverting the nozzle jet. Number of mentioned FTV types has been investigated and reported for planar 2D nozzles and some for the axisymmetric nozzles as well, appearing in the works of Wing and Guiliano, 2 Nielson et al, 3 Deere et al, 4 Zmijanovic et al 5 In the mentioned investigations, secondary injection thrust vector control (SITVC) efficiency was confirmed over wide range of pressure ratios which should satisfy needs for the second stage launcher nozzle operation envelope.…”

“…It is observable that both injectant and the bow shock exit the nozzle with shock reflection and mixing taking place in the exterior domain. The series of test with injector different position as reported in [5] naturally pointed that secondary injection closer to the nozzle exit steadily increases vectoring and nozzle performance because of larger nozzle expansion and by eliminating reflection, mixing and reattachment inside the nozzle. This is only opposed by the overexpansion regimes.…”

“…The investigation is then enlarged with number of numerical test models. Two conical nozzles with secondary injection placed at relative divergent positions x j /x t = 0.7 and x j /x t = 0.9 are previously tested with air to air cold flow experiments reported in Zmijanovic et al [5] and they are briefly given in the results section. Truncated ideal contour nozzle with injection at relative divergent position of x j /x t = 0.88 is fully investigated with full wall pressure mapping in cold flow experiments with air to air injection.…”

“…Namely, the Schilling criterion 14 based on cold flow experiments was used for separation pressure evaluation while Green criterion 15 combined with Mach relation for the plateau pressure as described in. 5 Accordingly, Billig 13 model for estimation of detached shock wave on conical nosed bodies in supersonic flow is adapted to conical nozzle case to delineate separation line delimiting the separation area upstream of the injector. …”

Cooling of the Vulcain Nozzle’s Divergent Wall

“…This technique is not only designed to guarantee a good cooling efficiency, but it contributes also in delaying the restrained lift off & improves the thrust vectoring [2].…”