Transmission Oil Distribution and Thermal Behavior in Sikorsky S-76 Tail Rotor Gearbox

A computational methodology has been developed to calculate the effects of a splashing oil reservoir on the thermal behavior of a gearbox. The approach uses time-accurate CFD calculations of the oil distribution to provide appropriate boundary conditions for a thermal model of the solid components of the gearbox. This demonstration of a combined fluid motion and solid thermal analysis can be used to help optimize preliminary and existing designs. Computational results of the oil splashing are able to provide information about the bulk motion of the oil and its affect on local heat transfer coefficients to the solid components, as well as identify areas that may be oil flooded or starved. The fluid heat transfer coefficients are then applied to a thermal model of the full transmission housing to predict local component temperatures.