Performance optimization of convergernt – Divergent nozzle under different inlet conditions

The objective of this work is to design a CD nozzle (Convergent-Divergent Nozzle) with the help of 3D modeling software and to fabricate a model of the same scale. Three models with same inlet and throat diameter are taken. The only difference between them is the exit diameter. The flow parameters are analyzed both analytically and experimentally. From the literature survey we can find that, there lies an effect of Nozzle Pressure Ratio (NPR) on the exit velocity of the nozzle. Therefore, these models are tested at different inlet pressures. The data that are acquired analytically and experimentally are fed into software tool for optimization. Response surface model is created to find the amount of variation between the analytic outcome and experimental outcome. Through series of calculation in the software tool an optimum value for the NPR is found. The optimum NPR thus found is the NPR for which the exit velocity is highest. Thus, choosing such NPR for operation increases exit velocity of the nozzle which in turn increases the velocity of the vehicle. Thereby increasing the efficiency of the nozzle.