Abstract:
The increasing demand for higher performance in rocket launchers promotes the development of optimized nozzle contours, for which the nozzle length is minimized. How-ever, this may lead to flow separation and subsequent unsteady, asymmetric forces, so-called side-loads, which may be detrimental to the nozzle structures and other engine components. In the early phases of the launch, the nozzle jet is over expanded, and separation can occur within the nozzle (below the full flowing regime). Depending on the nozzle contour, two types of separation can occur, namely, free and restricted shock separation. These two cases have been the subject of several experimental, theoretical and numerical studies in the past decades, and a number of models and hypotheses for its prediction have been developed. Pioneering 3D DES results from ONERA for a Thrust-Optimized Contour nozzle investigated atLabratoire d`Edutes Aerodynamiques (LEA), denoted LEA-TOC nozzle, satisfactorily reproduced the unsteady features of the flow (e.g. wall pressure rms profile and spectrum). There is however room for improvement regarding the prediction of the position of the separation point and the value of the mean pressure recovered downstream of shock-boundary layer interaction. On the other hand, it is known that, in a strong-shock/boundary layer interaction, the realizability constraint is violated in the outer part of the layer and outside.
Page(s):
190-196
DOI:
DOI not available
Published:
Journal: Proceedings 6th International Bhurban Conference on Applied Sciences and Technology , Volume: 1, Issue: 0, Year: 2009