Considering the time-varying contact line length and gear tooth load during a meshing cycle

and combining the transient equivalent curvature and entrainment velocity along the contact line

a thermal elastohydrodynamic lubrication (TEHL) model of finite line contact for helical gears was developed under non-Newtonian fluid and big slide-roll ratio for the aerospace transmission. By employing multilevel method and sequential sweeping method

the complete TEHL numerical solution suitable to wide working conditions was obtained. The thermal friction performances for helical gears transmission were investigated in non-Newtonian fluid and big slide-roll ratio cases. Results showed that at the end of helical gears the obvious pressure and temperature peak existed

moreover the film thickness reduced slightly approaching to the engage-in position. Non-Newtonian characteristics exerted a significant influence on temperature

furthermore the temperature distribution behaved like a V-shape around the pitch point. The friction coefficient of the pitch point along the meshing line was close to zero

which gradually increased towards the two sides and with the going up of slide-roll.