Control Forces in Rocket Nozzles Produced by a Secondary Gas Stream Inclined at Various Angles to the Nozzle Axis

Abstract

The side force produced by the injection of secondary gas into the supersonic regime of a main nozzle is investigated with particular reference to the effect of the angle between the secondary jet and the main nozzle axis. In the experiments, downstream and upstream injection angles at one secondary port location in the main nozzle were examined. It is shown that there is a definite advantage to be gained by injecting the secondary gas in an upstream direction. An analytical analysis of the results indicates that for moderate secondary mass flows maximum side force is produced when the angle between the axis of the secondary port and the normal to the axis of the main nozzle is in the range 40-50°. When injecting a given secondary mass flow at the angle for maximum side force the axial thrust augmentation is almost zero. As the angle of injection is reduced from upstream values to downstream values the side force reduces and the thrust augmentation increases, indicating that thrust augmentation can be used to determine how effectively a given mass flow of secondary fluid is being utilized in the production of side force.

Thrust vectoring effects of a transverse gas injection into a supersonic cross flow of an axisymmetric convergent-divergent nozzle

“…Other than position of the injection port, the angle of injection and shape of the injection represent geometrical parameters that need to be considered in SITVC optimization process. As previously reported by Nielson et al [19], it is found that secondary injection inclined upstream with respect to the nozzle axis has positive e¨ect on the main §ow de §ection until some experimentally found breakdown value. Injection with upstream inclination angle causes ¤pushes¥ of the edge of a bow shock upstream in §icting stronger adverse pressure gradient and early separation (see Fig.…”

“…In the experiments and preliminary numerical simulations, transverse injection is normal to the nozzle axis. As it is reported by Nielson et al [19] and Deere [4], upstream inclined injection has augmenting e¨ects on the side force and vector de §ection angle δ. In order to investigate upstream inclined injection e¨ect, injectors inclined upstream ranging from 20…”

“…The circular injection with inclination from the nozzle axis has been investigated experimentally by Nielson et al [19] and also by Masuya et al [18]. Nielson et al [19] performed the experiments on series of the circular sonic injections of f m ∼ 0.06 under di¨erent angles.…”

“…Nielson et al [19] performed the experiments on series of the circular sonic injections of f m ∼ 0.06 under di¨erent angles. It is found that downstream inclined injection has a negative effect on the side force while the upstream inclined angles positively a¨ect the de §ection until some limiting breakdown value.…”

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.…”