Suppression of Thermal Emission from Exhaust Components

Thermal signatures generated by hot components or hot engine exhaust gases can be suppressed by mixing cool ambient air with the hot component gas stream. In the development of signature reduction concepts, it is desirable to obtain a better understandingof the physical flow processes, hardware parameters and potential configurations that can be use for optimization of the signature suppression methodology and thus enhance the suppression. This screening process will be performed using one dimensionalmixing equations, ejector performance analysis and Computational Fluid Dynamics (CFD). Suppression methods such as film cooling, ambient air mixing and ejector design can be very effectively evaluated with the use of these design techniques. The CFDevaluation will result in guidelines for the design, fabrication and subsequent testing of the most promising concept(s). The methods used are also applicable to evaluating the performance of fullscale hardware. A theoretical and design effort is proposed,where one dimensional mixing analysis, ejector analysis and CFD techniques will be employed for evaluation of potential IR suppression techniques. The proposed effort would reduce IR suppression development costs, development time and permit IRsuppression optimization.IR suppression devices have application in reducing the hazard of burns due to hot components that are encountered in every day civilian equipment such as commercial aircraft jet engines, automotive exhaust pipes, electric motors,aircraft ground support machinery, portable power generators and similar equipment. Excess noise and heat also represents a hazard to ground personal that work in close proximity to aircraft. High performance mixing devices will permit optimization andimproved efficiency of gas turbine engines burner cans.