Effect of ambient pressure on the mixing efficiency of impinging doublets is experimentally investigated for similar and dissimilar orifice diameter impinging jets with non-gelled and gelled propellant simulants. For similar orifice diameter impingement, the ambient pressure increase above atmospheric pressure enhances mixing for both gelled and non-gelled fluid. However, the mixing efficiencies stop increasing at and remain constant above a certain ambient pressure. Gelled simulant generally results in poorer mixing than the non-gelled simulant, suggesting the momentum carried by jets and pre-impingement jet conditions are the determining factor in mixing efficiency. For dissimilar orifice-diameter impingement cases, the mixing is generally constant over all ambient pressures. The equal jet velocity cases (momentum ratio = 0.5) produce better mixing than equal momentum ratio cases (momentum ratio = 1.0) or equal jet volumetric flow rate cases (momentum ratio = 2.0). The equal jet volumetric flow rate cases (momentum ratio = 2.0) results in worst mixing, regardless of ambient pressure and jet velocity for the range of pressures and velocities tested. For some optimized operating conditions, the dissimilar orifice-diameter impingement case can produce better mixing than the similar orifice diameter impingement case.
展开▼
