用二维简化模型计算连续波HF化学激光器特性

<正> 利用二维流体力学简化模型求解两股平行流的扩散混合和化学反应问题,得到连续波HF化学激光器谐振腔中气流混合界面,不同振动能级的HF活性分子浓度及小信号增益曲线。

扩散型连续波HF化学激光器小信号增益的计算

应用层流边界层二维简化模型计算了扩散型连续波HF化学激光器的小信号增益。研究了气流速度、温度、组份对增益的影响,得到一些有用的结果。计算结果与二维Navier-Stokes方程组的计算结果相符,但计算方法较简单。

反应速率系数对HF化学激光器增益特性的影响

本文研究了HF化学激光器中两股平行气流的速度比和动力学速率系数的不确定性对增益系数的影响。指出HF(V)-H是最快的碰撞弛豫过程,其速率系数值对估算的增益系数有较大影响。

连续波HF化学激光器计算浓度场的简化模型

介绍一个计算连续波HF化学激光器浓度场的简化模型。假设速度场与普通平板边界层速度场相似。温度场与浓度场是用联立能量与组份守恒方程以及相似的速度场求解得到的。求得了混合、化学反应区的界面曲线,并研究了气流速度、温度以及化学反应等对激发态HF浓度的影响。

应用在HF化学激光器上的超音速引射器

<正> 本文根据流体力学守恒方程,探讨采用气体引射技术将化学激光器的低总压、低腔压气流排入大气的问题,并提出一个具体方案。如果能够实现,对于化学激光器或其他类型高能激光器的探索研究将具有实际意义。被引射气流的计算压力为5托,温度为300K,气流速度 M=4,气体组份为40%H_2,60%He。引射气体采用高压的 N_2,H_2及高温的 H_2O。计算结果表明,利用常温 N_2作为引射气体效果不好。利用10大气压的 H_2可以引射光腔尾气。如果被引射气体预先扩压至70托,引射器混合段保持超音速气流,则引射气体的用量和被引射气体用量相同。利用 H_2O 作为引射气体,H_2O 温度最好超过1700K。计算发现,分子量较大的气体不易引射分子量较小的气体。混合段保持超音速气流时引射器出口总压力比混合段为亚音速时为高。扩压器的总压恢复系数对引射器的出口总压影响很大。本文给出一个超音速引射器设计方案,可作为参考.

应用在HF化学激光器上的超音速引射器

<正> 高能化学激光器,除了用庞大的真空系统,泵浦尾气以外,目前正在探索,亚音速-超音速引射器和超音速-超音速引射器泵浦系统(后面简称为超音速引射器)。

Wave pattern characteristics of a two-phase nozzle flow by shock propagation

In this paper, the wave pattern characteristics of shock-induced two-phase nozzle Hows with the quiescent or moving dusty gas ahead of the incident-shock front has been investigated by using high-resolution numerical method. As compared with the corresponding results in single-phase nozzle flows of the pure gas, obvious differences between these two kinds of flows can be obtained.

Dynamic analysis of arrest of buckle propagation on a beam on a nonlinear elastic foundation by FEM

Based on the dynamic governing equation of propagating buckle on a beam on a nonlinear elastic foundation, this paper deals with an important problem of buckle arrest by combining the FEM with a time integration technique. A new conclusion completely different from that by the quasi-static analysis about the buckle arrestor design is drawn. This shows that the inertia of the beam cannot be ignored in the analysis under consideration, especially when the buckle propagation is suddenly stopped by the arrestors.

Experimental investigation on low-temperature fatigue crack propagation in offshore structural steel A131 under random sea ice loading

An apparatus of low-temperature controlling for fatigue experiments and its crack measuring system were developed and used for offshore structural steel A131 under conditions of both low temperature and random sea ice. The experimental procedures and data processing were described, and a universal random data processing software for FCP under spectrum loading was written. Many specific features of random ice-induced FCP which differed with constant amplitude FCP behaviours were proposed and temperature effect on ice-induced FCP was pointed out with an easily neglected aspect in designing for platforms in sea ice emphasized. In the end, differences of FCP behaviours between sea ice and ocean wave were presented.