Abstract
3 A simplified cooling device consisting of two parallel channels is used to simulate the regeneratively cooled structure of hypersonic vehicles. A concept of flow instability (SFI) is proposed in this paper. The SFI is similar to the ledinegg instability which is primary found in the two-phase flow boiling system to explain the static flow excursion. But for hydrocarbon fuel, SFI may take place in the cooling structure at high temperature and supercritical pressure. A model is constructed to analyze the mechanism of the SFI. The pressure drop vs. flow characteristic curves are calculated from the thermopysical properties of hydrocarbon fuel, which include the heat sink and density. Experiments verify that the model is feasiable, though the accuracy of density of hydrocarbon fuel is still need to improve. At a given heating power, the pressure drop vs. flow characteristic curve is a N- type one, which makes the same pressure drop at different mass flow rates. That triggers the SFI. Chemical craking makes the SFI much more complicated. At the relevant pressure, the pressure drop vs. flow characteristic curve becomes a quintic curve. More extreme points on the curve induces more instability.
Published Version
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