【Daily Question】Theoretical Foundation 2021.04.20
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Multiple-choice question: The question is shown in the image ( ). Answer: D. Hint: An additional reward will be given to those who can explain the solution process; the answer can be submitted there
In nozzle D, the critical pressure ratio is the ratio of critical pressure to stagnation pressure, that is, β=. In the formula, k is the adiabatic index. The isentropic flow of water vapor is relatively complex; to simplify the calculations, it is assumed that the isentropic flow of water vapor also follows the aforementioned formula. For superheated steam, take k=1.3; substituting this value into the above equation yields β=0.546.
The isentropic flow of water vapor is quite complex. To simplify the calculations, it is assumed that the isentropic process of water vapor also satisfies the relationship pVk = constant. For superheated steam, take k=1.3 and β=0.546; for dry saturated steam, take k=1.135 and β=0.577