The improvement of overall performance in power t mass ratio of modern gas tubines can greatly be contributed to the effective ooling of the tubine blades. Optimization of coolant performance is essential as the coolant flow introduces losses which need to be minimized. This paper ntroduces a new model to simulate heat transfer in ribbed channels. In the ribbed sections large variations in tubulence levels occure and the secondary flows associated with these ribs are responsible ofr significant local heat transfer variations. Furthermore, the ribs produce a complex flow structure so that there is continuing need for a better undrstanding of the flow physics i nribbed ducts. A finite differnce simulation of the fluid flow and temeprature distribution in the inlet section of the cooling channel of a typically colled burbine blade is used t oevaluate the new model. Various configurations of rib turbulators in the blade passages were simulated. In the case of the 45degC angled ribs, there is a strong sideways secondary flow component which produces bot increased overall heat transfer as well as asymmetrical local heat transfer enhancement. The results show the flow structure and heat transfer enhancement and corrleate local heat transfer variations to secondary flow details. In general the predicated heat transfer rates compate well with measured data for 90degC ribs, but further work needs to be done to accurately model angled ribs.
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