1 Computational and Experimental Investigation of Inclined Choked Injection of Gaseous Jet S. Srivastava, A. M. Sheridan, and M. Henneke John Zink Hamworthy Combustion, Tulsa, OK 74116 and K. A. Sallam 1 Oklahoma State University, Tulsa, OK 74106 The injection of choked gaseous jets into still air is investigated computationally and experimentally. The objective is to compare the performance of three turbulence models – Realizable k-, SST k- and Reynolds Stress Transport to resolve the effect of injection angle on the jet mixing with ambient air. The experimental methods consist of particle image velocimetry (PIV) using pulsed Nd:YAG lasers of a choked gas jet, seeded with aluminum oxide particles, injected into still air that has been seeded with water fog. The test conditions include injection angles of 0° and 15°. The results including jet velocities and the vorticity field are presented. The flow field is not symmetric along the injection axis due to the asymmetric triggering of expansion fans at the jet exit due to the inclined injection plane. Moreover, the numerical simulation reveals the complex interaction mechanism of the expansion fans and shockwaves within the injection port. I. Introduction hoked jets are investigated in this study motivated by their applications in gaseous fuel injection in flares and furnaces. Gas jet injection from an underexpanded nozzle is associated with the formation of shock diamonds [1]. This wave pattern plays an important role in jet mixing [2-5]. Computational results of under-expanded jet flow [6] are easily validated with the theory of gas dynamics (Prandtl-Meyer expansion fans and oblique shock waves) and experimental data of Mach disk location and size [7]. There is a need, however, to investigate the effects of the injection angle on the exit flow structure and the jet mixing with ambient still air. The objective of this study is to develop the computational methods to resolve the inclined choked jets with applications to gaseous fuel injection. II. Experimental and Computational Methods The following section describes the experimental setup used to measure the velocity field of choked inclined jets and the computational models tested in the current study. A. Experimental Methods The experimental setup used for this research is multifaceted containing several systems that are separate but used in conjunction with each other to collect data. The various systems (Fig. 1) include a pressure delivery and seeding system, laser and laser sheet optics, and a triggered PIV camera used to capture the image pairs. See Fig. 2 for the overall PIV system. The pressure delivery system for the experimental setup consists of many key components. First of which is the solid particle seeding chamber. The nozzle to be tested is mounted in the top of the seeding chamber via a 1” NPT threaded connection (Fig. 2). A pressure gauge (PG-201) is mounted just upstream of the orifice to measure chamber pressure. This pressure is critical as it is the variable used to determine if the chamber pressure is high enough to achieve choked flow through the nozzle as it relieves to the ambient condition. The chamber pressure is also used to 1 Corresponding author: (405)762-0749, sallam@okstate.edu. Associate Professor, Associate Fellow AIAA. C