Compared with direct ablation,a prepulse is used to propulsion. It is found that the coupling coefficient is beam and the prepulse. At a delay time of 12 ns,the × 10^-5 N/W. enhance the coupling coefficient in la...Compared with direct ablation,a prepulse is used to propulsion. It is found that the coupling coefficient is beam and the prepulse. At a delay time of 12 ns,the × 10^-5 N/W. enhance the coupling coefficient in laser plasma related with the delay times between the main coupling coefficient reaches the maximum of 5.8展开更多
The boiling behavior of the liquid nitrogen (LN2) under the transient high heat flux urgently needs to be researched systematically. In this paper, the high power short pulse duration laser was used to heat the satura...The boiling behavior of the liquid nitrogen (LN2) under the transient high heat flux urgently needs to be researched systematically. In this paper, the high power short pulse duration laser was used to heat the saturated LN2 rapidly, and the high-speed photography aided by the spark light system was employed to take series of photos which displayed the process of LN2's boiling behavior under such conditions. Also, a special temperature measuring system was applied to record the temperature variation of the heating surface. The experiments indicated that an explosive boiling happened within LN2 by the laser heating, and a conventional boiling followed up after the newly-defined changeover time. By analyzing the temperature variation of the heating surface, it is found that the latent heat released by the crack of the bubbles in the bubble cluster induced by the explosive boiling is an important factor that greatly influences the boiling heat transfer mechanism.展开更多
文摘Compared with direct ablation,a prepulse is used to propulsion. It is found that the coupling coefficient is beam and the prepulse. At a delay time of 12 ns,the × 10^-5 N/W. enhance the coupling coefficient in laser plasma related with the delay times between the main coupling coefficient reaches the maximum of 5.8
文摘The boiling behavior of the liquid nitrogen (LN2) under the transient high heat flux urgently needs to be researched systematically. In this paper, the high power short pulse duration laser was used to heat the saturated LN2 rapidly, and the high-speed photography aided by the spark light system was employed to take series of photos which displayed the process of LN2's boiling behavior under such conditions. Also, a special temperature measuring system was applied to record the temperature variation of the heating surface. The experiments indicated that an explosive boiling happened within LN2 by the laser heating, and a conventional boiling followed up after the newly-defined changeover time. By analyzing the temperature variation of the heating surface, it is found that the latent heat released by the crack of the bubbles in the bubble cluster induced by the explosive boiling is an important factor that greatly influences the boiling heat transfer mechanism.
