本文以雙流體模型來研究收縮、擴張噴嘴中之兩相汽泡流。物理模型中包含了汽泡相對於液體之徑向運動及滑動等動力效應。計算結果顯示，本文模型可準確地預測次音速汽泡流場。同時，我們也計算了Muir and Eichhorn （1963）的超音速汽泡流，在他們的實驗中，Muir and Eichhorn發現當流場為阻流狀態時，臨界壓力比（定義為喉部阻流壓力和上游壓力之比值）及臨界質量流率大於均質流模型的分析結果。由於Muir and Eichhorn量測到汽液兩相間存在相當的速度差，因此他們推測此誤差是由於均質流模型忽略兩相相對運動效應所造成的。本文模型證明可準確地預測兩相間之相對速度，對臨界質量流率之預測亦相當精確，但卻無法有效改善臨界壓力比的誤差，我們推測應是流場之高維效應所致。本文同時亦探討了超音速汽泡流中噴嘴下游之流場特性，證明汽泡震波之存在，且其前後之壓力比與Thang and Davis （1981）所推導的Hugoniot 關係式相當符合。為了正確選用分析模型中參數的值，本文亦探討了Rayleigh-Plesset方程式中等效黏滯係數的大小對流場可能造成之影響，以作為計算的依據。同時，為了更真實地描述汽泡在體積變化過程中，熱擴散效應對流場所造成之影響，我們修正了Reyleigh-Plesset方程式以得到含有熱阻尼之汽泡流分析模型，並重新計算熱阻尼對次音速及超音速流場所造成的影響。結果發現熱阻尼效應會使汽泡流場從準靜不穩定(即閃變流)變為穩定。

One-dimensional bubbly flows through converging-diverging nozzles are investigated using a two-fluid model. Effects associated with both translational and radial relative motions between bubbles and liquid are incorporated. Calculation of a subsonic case is performed first and shows good agreement with experiments. The model is then applied to critical (or choked) flow situations studied previously by Muir and Eichhorn (1963). In their experiments, Muir and Eichhorn found larger critical pressure ratios (which are defined as the ratio of the pressure in the throat to that in the reservoir under choked conditions) and flow rates than homogeneous flow theory. They measured significant slip between phases which, therefore, was speculated to be responsible for these discrepancies. It is demonstrated in this paper that the phase relative velocity and mass flow rates can be predicted reasonably well (within the experimental uncertainly) using the present model, however, can not fully compensate the critical pressure ratio. Other important features of the critical flows are also explored, including the formation of compression shock waves present in the divergent part of the nozzle. Our computations show that the pressure ratio across the shocks agree very well with the Hugoniot relation established by Thang and Davis (1981). We also examine the sensitivity of the flow field to the value the effective viscosity employed in the Rayleigh-Plesset equation. In order to describe the effects of heat diffusion during the variation of bubble volume, we modify the Rayleigh-Plesset equation to in corporate the thermal damping into the present model. Both the subsonic flows and the supersonic flows are revisited. Results obtained show that the flashing instability of the bubbly flows can be stabilized by the thermal damping effects.

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