動載作用下管內(nèi)氣(汽)-水兩相流動及其沸騰換熱研究.pdf

1、南京航空航天大學(xué)博士學(xué)位論文動載作用下管內(nèi)氣（汽）-水兩相流動及其沸騰換熱研究姓名：姚秋萍申請學(xué)位級別：博士專業(yè)：人機(jī)與環(huán)境工程指導(dǎo)教師：宋保銀2010-06動載作用下管內(nèi)氣（汽）- 水兩相流動及其沸騰換熱研究 II Abstract Based on the existing research results at home and abroad, the experimental research of

2、flow and heat transfer characteristics of air/steam- water two- phase flow in pipes under high gravity, the identification of flow pattern, and the development of the physical model and its nume

3、rical method were conducted. The obtained results are significant in developing airborne vapor cycle cooling system and can be added in the database in investigating the characteristics of gas- l

4、iquid two- phase flow and heat transfer. The rotating platform was established to simulate the dynamic load, o n which a circular loop of air/steam- water two- phase flow circulation pipeline was insta

5、lled and adjusted. The parameter measurement, data acquisition and processing, and the heating of air/steam- water two- phase flow under rotation condition were solved. The visual observation and real

6、 time record of flow pattern under high gravity were realized using visual technology. By changing the parameters, such as the orientation and inclination of the test pipe, rotating speed, inl

7、et temperature, flow rate, and etc, the data of air/steam- water two- phase flow including its heat transfer under rotation condition for diffirent orientations and inclinations of the test pipe

8、 were obtained. By processing and analyzing the original data, the effects of acceleration on void fraction, flow rate, flow velocity, temperature, pressure and pressure drop of air/steam- water

9、two- phase flow and the characteristics of the air/steam- water two- phase flow and boiling heat transfer under high gravity were obtained. The results show that the acceleration significantly infl

10、uences the flow characteristic and boiling heat transfer of the two- phase pipe flow. As the direction of the dynamic load and the flow direction are opposite, the greater the dynamic load, t

11、he lower the flow rate, the higher the pressure drop and the flow resistance, and the more obvious the trend of blocking the fluid flow. The outside heat transfer coefficient increases with

12、the increase in dynamic load. Therefore, the dynamic load will enhance heat dissipation and reduce the heat transferred to the two- phase fluid and the pipe wall temperature. Through visual te

13、chnology, the novel flow patterns such as impact flow and impact mixing flow under high gravity were found in the present work. The physical models including centrifugal force and Coriolis forc

14、e for gas- liquid two- phase flow with homogeneous fluid and separated fluid were developed. The non- dimensional analysis of governing equations were carried out. The mesh generation for two kind