عنوان مقاله [English]
The study of cooling procedure in Methane-Based propulsion systems is one of the main steps in designing sub-systems and thermal protection of the engine structure. The coolant fluid inside the cooling channels may experience flow regime change and heat transfer deterioration. Heating methane at super-critical pressure results in a higher than pseudo-critical temperature and pseudo-phase change happens. Furthermore, in critical conditions, there is the possibility of heat transfer deterioration at high heat fluxes and low mass fluxes. In these areas, heat transfer from the wall to the fluid is disturbed due to the decrement in the heat transfer coefficient. Also, the wall temperature increases and there is the melting possibility of the engine wall. As a result, the study of this phenomenon is important for the thermal analysis of cryogenic methane for cooling applications. In the present article, a three-dimensional solver is developed for the simulation of the conjugate heat transfer inside a rectangular channel with trans-critical methane coolant. A finite volume scheme is utilized for the discretization of the governing equations. An iterative solution method based on the SIMPLEC algorithm is used to solve the equations. The solver is developed based on the thermodynamic and transport property relations corresponding to the coolant flow conditions in the trans-critical regime. The parametric study of the heat transfer deterioration phenomena is conducted utilizing the conjugate heat transfer simulations results of methane inside the MTP channel for heat transfer rate, inlet pressure and temperature, inlet mass flux, and different surface roughness. Further, a few relations are derived for predicting the onset of methane heat transfer deterioration along the rectangular cooling channel in a range of pressure from 6 MPa to 20 MPa. The relative error of derived relations with numerical data is less than 1 percent. Finally, some methods for controlling the heat transfer deterioration phenomena have been presented.