段塞流引起的不稳定流体力使得立管振动更为复杂。基于VOF(volume of fluid)多相流模型对气液变化进行追踪,通过单向流固耦合方法得到含段塞流的缓波形立管振动响应。探究由表观液速引起的气液比变化对立管高曲率位置振动响应的影响,通...段塞流引起的不稳定流体力使得立管振动更为复杂。基于VOF(volume of fluid)多相流模型对气液变化进行追踪,通过单向流固耦合方法得到含段塞流的缓波形立管振动响应。探究由表观液速引起的气液比变化对立管高曲率位置振动响应的影响,通过时域和频域的分析发现:随着气液比的增大,立管顺流向和垂向位移先增后减并表现为驻波特性,而横流向位移先减后增,测点相位差体现行波特性。频率方面,横流向不同测点的主振频率不同。随气液比的增大,一阶和二阶频率对位移贡献的差值减小,模态竞争加剧。研究结果可为立管流致振动研究提供参考。展开更多
Experimental research was conducted on the performance curves and the cavity evolution for different flow and geometric parameters in jet pumps for zero flow ratio(ZFR)conditions.New pressure ratio,Pr,flow ratio,qr,we...Experimental research was conducted on the performance curves and the cavity evolution for different flow and geometric parameters in jet pumps for zero flow ratio(ZFR)conditions.New pressure ratio,Pr,flow ratio,qr,were used in place of the conventional performance parameters h,q,to characterize the jet pump flow performance.A super cavitation cavity in the jet pump was observed to fill most of the flow channel,which hindered further increases of the flow rate and increased qr to one,thus,created a critical point on the new P_(r)-q_(r)^(2)curve.Before the critical point,P_(r)was proportional to q_(r)^(2)with a coefficient that was much more sensitive to the area ratio than the relative throat length and the diffusion angle.After the critical point,the flow rate reached its maximum,the limiting flow rate,which only depended on the total inlet pressure and the area ratio.The total inlet pressure was proportional to the square of the limiting flow rate with a flow coefficient that was only a quadratic function of the area ratio.展开更多
文摘段塞流引起的不稳定流体力使得立管振动更为复杂。基于VOF(volume of fluid)多相流模型对气液变化进行追踪,通过单向流固耦合方法得到含段塞流的缓波形立管振动响应。探究由表观液速引起的气液比变化对立管高曲率位置振动响应的影响,通过时域和频域的分析发现:随着气液比的增大,立管顺流向和垂向位移先增后减并表现为驻波特性,而横流向位移先减后增,测点相位差体现行波特性。频率方面,横流向不同测点的主振频率不同。随气液比的增大,一阶和二阶频率对位移贡献的差值减小,模态竞争加剧。研究结果可为立管流致振动研究提供参考。
基金supported by the National Natural Science Foundation of China(Grant Nos.12072243,12102308).
文摘Experimental research was conducted on the performance curves and the cavity evolution for different flow and geometric parameters in jet pumps for zero flow ratio(ZFR)conditions.New pressure ratio,Pr,flow ratio,qr,were used in place of the conventional performance parameters h,q,to characterize the jet pump flow performance.A super cavitation cavity in the jet pump was observed to fill most of the flow channel,which hindered further increases of the flow rate and increased qr to one,thus,created a critical point on the new P_(r)-q_(r)^(2)curve.Before the critical point,P_(r)was proportional to q_(r)^(2)with a coefficient that was much more sensitive to the area ratio than the relative throat length and the diffusion angle.After the critical point,the flow rate reached its maximum,the limiting flow rate,which only depended on the total inlet pressure and the area ratio.The total inlet pressure was proportional to the square of the limiting flow rate with a flow coefficient that was only a quadratic function of the area ratio.
