Papers by Author: Tao Nie

Abstract: The cooling effect of a film cooling thermal protection system is investigated, and the flow field, aerodynamic force and surface temperature distribution are obtained. The numerical method is validated by experiment with no film cooling. The physical mechanism of the reduction of temperature is analyzed. The jet interacts with the free stream to form a thermal insulating layer on the wall, which enables the free stream to flow outside the wall rather than interact with the surface to produce aerodynamic heating. In addition, the film cooling flow form a cool recirculation region, which reduces the temperature on the surface. Analysis of the numerical simulation results shows that this kind of thermal protection system has an excellent cooling effect on the surface of the nose-tip. With the outlet speed increasing, the cooling efficiency is improved and the aerodynamic resistance is changeless. When outlet speed and total pressure are invariable, the cooling effect of air and nitrogen is the same, but the cooling effect of helium is better.

Abstract: Four turbulent models are introduced. The hypersonic aerodynamic heating calculation results by Shear Stress Transport (SST) turbulent model of different grid scale shows that near wall y+ spacing approximate to one third of the upper limit prescribed by turbulent model. Then, the comparison of the hypersonic aerodynamic heating calculation results by different turbulent model and the test data shows that SST turbulent model can give an enough accurate result.

Abstract: By the use of the map of the thermal resistance among volume cells, we establish a coupled heat transfer model of the hot gas, chamber wall and coolant. A reduced one-dimensional model was employed for the coolant flow and heat transfer, and three dimensional heat transfer model was used to calculate the coupling heat transfer through the wall, considering heat transfer at circumferential direction, axial direction and radial direction. Based on the study the mechanism of the cooling structure heat transfer, the computing model was employed and achieved the rule of heat flux and temperature of gas wall. Simultaneously, influence of different cooling structure was performed. The results indicated that the cooling structure with raised structure could better reduce the temperature of the chamber wall.

Abstract: To study the effects of wall thickness, rib height and groove width on cooling effect and pressure drop, three dimensional heat transfer of liquid propellant rocket engine with cooling groove is numerically investigated using gas-solid-liquid coupled heat transfer model. The one-dimensional model is adopted to describe the coolant flow and 3D heat transfer model is used to calculate the coupling heat transfer through the wall. In this text, wall thickness, rib height and groove width varied while the groove number is fixed and coolant mass flow rate remains constant. When liner material is QZr0.2 alloy, we find the optimal design point of the aspect ratio. Moreover, a fitting function of the optimal aspect ratio is acquired. The biggest error of the fitting function is 3.3% compared with numerical results.

Abstract: To obtain temperature distribution in regenerative-cooled liquid propellant rocket nozzle quickly and accurately, three-dimensional numerical simulation employed using empirical formulas. A reduced one-dimensional model is employed for the coolant flow and heat transfer, while three dimensional heat transfer model is used to calculate the coupling heat transfer through the wall. The geometrical model is subscale hot-firing chamber. The numerical results agree well with experimental data, while temperature field in nozzle obtained. In terms of computing time and accuracy of results, this method can provide a reference for optimization design and performance estimation.