Rotational effects on impingement coolingThe present consideration of rotation effects on heat transfer in a radially exhausted, impingement-cooled turbine blade model gives attention to experimental results for Reynolds and Rossby numbers and blade/coolant temperature ratio values that are representative of small gas turbine engines. On the basis of a model that encompasses the effects of Coriolis force and buoyancy on heat transfer, bouyancy is identified as the cause of an average Nusselt number that is 20-30 percent lower than expected from previous nonrotating data. A heuristic model is proposed which predicts that the impingement jets nearest the blade roots should deflect inward, due to a centripetal force generated by their tangential velocity counter to the blade motion. Potentially serious thermal stresses must be anticipated from rotation effects in the course of blade design.
Epstein, A. H. (Massachusetts Inst. of Tech. Cambridge, MA, United States)
Kerrebrock, J. L. (Massachusetts Inst. of Tech. Cambridge, MA, United States)
Koo, J. J. (Massachusetts Inst. of Tech. Cambridge, MA, United States)