Abstract: Based on computational fluid dynamics/infrared radiation (CFD/IR) numerical calculations and validated by experiment, the effect of nozzle pressure ratio and geometry-vector angles of a single expansion ramp nozzle (SERN) on its aerodynamic and infrared radiation characteristics is studied. The results show that when the geometry-vector angle is 0癮nd the nozzle pressure ratio is low, the aerodynamic characteristic of the nozzle decreases significantly, largely because of over expansion. When the geometry-vector angle is negative, over expansion is more serious and aerodynamic characteristic decreases. With the increase of the absolute value of the geometry-angle, the vector thrust increases, but the thrust coefficient decreases. When the geometry-vector angle is changed from -25? to 25癮nd the nozzle pressure ratio is changed from 3 to 6,the smallest thrust coefficient is about 0.88 and the biggest thrust coefficient is about 0.98. When the geometry-vector angle is 5?, the infrared radiation of the plume is biggest. When the geometry-vector angle moves away from 5?, the infrared radiation of the plume becomes smaller, but its distribution is not changed. With the variation of the geometry-vector angle, the total infrared radiation of the nozzle presents a different distribution. When the geometry-vector angle is negative, the detecting angle with large infrared radiation is at the underside. When the geometry-vector angle is positive, the upside of the nozzle has large infrared radiation. These are determined by the visible area of the inner wall of the ramp and nozzle lumen.

Key words: single expansion ramp vector nozzle, computational fluid dynamics, numerical simulation, aerodynamic performance, infrared radiation