ترجمه مقاله نقش ضروری ارتباطات 6G با چشم انداز صنعت 4.0
- مبلغ: ۸۶,۰۰۰ تومان
ترجمه مقاله پایداری توسعه شهری، تعدیل ساختار صنعتی و کارایی کاربری زمین
- مبلغ: ۹۱,۰۰۰ تومان
The modeling of trans- and supercritical mixing and combustion introduces considerable challenges for predictive rocket combustion simulations. Near the critical point, the thermo-physical properties of fluids undergo drastic changes that occur in the absence of a phase change. At these extreme pressure conditions, the repulsive atomic forces become important enough to overcome the surface tension and create a single-phase, dense fluid that shares the properties of a gas (e.g., high diffusivity) and a liquid (e.g., high density). In the transcritical regime, mixing is primarily a diffusion driven process in which the thermo-physical properties are non-linear functions of local pressure and temperature. Given the liquid-like density near the critical point, the fluid is prone to extreme density gradients in an otherwise continuous medium. For example, at a pressure of 5.5 MPa, the density of transcritical oxygen decreases, on average, by over 46 kg/m3 per degree Kelvin between 150 K and 160 K. Similarly, the specific heat at constant pressure varies by a factor of 10 within this same range, see Figure 1. This highly non-linear behavior near the critical point is just one example of the inability of the ideal gas law to relate the thermo-physical states. This strongly non-linear behavior is at the heart of the challenges in real fluid modeling and simulation.