A Thermal-Fluid-Structural model is presented for quantifying the heat generation by the labyrinth seal in the low-pressure turbine stator well cavity. The method combines windage heating and convective heat transfer effects for labyrinth seal design, making it possible to use the heat transfer boundary condition instead of adiabatic to do the computational fluid dynamic calculation. The solutions illustrate how the outlet total temperature may change depending on the seal pressure ratios, windage heating, and heat transfer coefficient. It is further demonstrated that with a fixed seal pressure ratio, the thermal boundary condition has little influence on the leakage flow rate of the seal. The total temperature rise is dependent on the thermal boundary conditions, including the stator/rotor wall temperature, heat transfer coefficient, and windage heat caused by air friction.