The flow disturbance and heat transfer mechanism in the tube bundle of rod baffle shell-and-tube heat exchanger were analyzed, on the basis of which and combined with the concept of heat transfer enhancement in the co...The flow disturbance and heat transfer mechanism in the tube bundle of rod baffle shell-and-tube heat exchanger were analyzed, on the basis of which and combined with the concept of heat transfer enhancement in the core flow, a new type of shell-and-tube heat exchanger with combination of rod and van type spoiler was designed. Corresponding mathematical and physical models on the shell side about the new type heat exchanger were established, and fluid flow and heat transfer characteristics were numerically analyzed. The simulation results showed that heat transfer coefficient of the new type of heat exchanger approximated to that of rod baffle heat exchanger, but flow pressure drop was much less than the latter, indicating that comprehensive performance of the former is superior to that of the latter. Compared with rod baffle heat exchanger, heat transfer coefficient of the heat exchanger under investigation is higher under same pressure drop, especially under the high Reynolds numbers.展开更多
This paper presents the measurement of void fraction in a vapor-liquid two-phase flow system constituted by horizontal heated tube bundles. An advanced measuring system with single-fiber optical probes is developed. T...This paper presents the measurement of void fraction in a vapor-liquid two-phase flow system constituted by horizontal heated tube bundles. An advanced measuring system with single-fiber optical probes is developed. The optical couplings are used in the measuring system instead of beam-splitting lens. Measurement of void fraction has been carried out within the tube bundles of the two-phase flow test section. The measurements show that the tube bundles have significant effect on the profile of the void fraction.展开更多
基金Supported by the National Basic Research Program of China ("973" Project) (Grant No. 2007CB206903)the National Natural Science Foundation of China (Grant No. 50721005)
文摘The flow disturbance and heat transfer mechanism in the tube bundle of rod baffle shell-and-tube heat exchanger were analyzed, on the basis of which and combined with the concept of heat transfer enhancement in the core flow, a new type of shell-and-tube heat exchanger with combination of rod and van type spoiler was designed. Corresponding mathematical and physical models on the shell side about the new type heat exchanger were established, and fluid flow and heat transfer characteristics were numerically analyzed. The simulation results showed that heat transfer coefficient of the new type of heat exchanger approximated to that of rod baffle heat exchanger, but flow pressure drop was much less than the latter, indicating that comprehensive performance of the former is superior to that of the latter. Compared with rod baffle heat exchanger, heat transfer coefficient of the heat exchanger under investigation is higher under same pressure drop, especially under the high Reynolds numbers.
文摘This paper presents the measurement of void fraction in a vapor-liquid two-phase flow system constituted by horizontal heated tube bundles. An advanced measuring system with single-fiber optical probes is developed. The optical couplings are used in the measuring system instead of beam-splitting lens. Measurement of void fraction has been carried out within the tube bundles of the two-phase flow test section. The measurements show that the tube bundles have significant effect on the profile of the void fraction.
