液体动力加热器

哈尔滨航空工业集团机电公司与哈尔滨永安热能发展有限公司，联手乌克TEK机械研究所，共同开发“绿太阳”液体动力加热器，该产品是全新概念的供热产品，即利用“空化现象”将液体动能转化为热能，它改变传统的供热方式。“空化现象”是液体高速流经“空化发生器”，在其内表面产生接近真空的负压，使液体达到沸点而产生大量的微小气泡，在周围水压作用下，气泡经过撞击，内部急剧爆裂、相互摩擦，形成强大的冲击波，释放出巨大能量，从而使液体变热。

Analysis of ventilated cavitation around a cylinder vehicle with nature cavitation using a new simulation method

In the present paper, a new simulation method is developed for unsteady cavitating flow with air ventilation,which is very useful for alleviating the pressure oscillation in hydroturbine draft tube and reducing the drag force on an underwater vehicle. Because the fluid includes three components, i.e., the water, vapor, and air, the interactions between water–air and water–vapor are treated by applying the level set method, and the effect of surface tension is taken into account in governing equations. Further, the phase change between the water and the vapor is modeled by a homogeneous model,where the effect of air injection is considered by applying the air volume fraction in the mass transport equation. For calibration, the cavitating flows around a cylinder vehicle were simulated using the proposed method, and the numerical results were compared with the experimental data at three different ventilation conditions. The good agreement of cavitation evolutions between the simulation and the experiment indicated that the proposed method was acceptable for the simulation of ventilated cavitating flows with nature cavitation and would be usable for various engineering applications.Moreover, the vorticity analysis depicts that the vortex is closely related to cavitation evolution, and air injection much changes the vorticity production in cavitating flow. It was also revealed that vorticities only occurred in regions with high vapor/air volume fraction and the vortex stretching term created the most vorticities.

Anti-cavitation performance of a splitter-bladed inducer under different flow rates and different inlet pressures

The anti-cavitation performance of a high-speed centrifugal pump with a splitter-bladed inducer is investigated under different flow rates and different inlet pressures. Simulations and external characteristics experiments are carried out. Static pressure and the vapor volume fraction distributions on the inducer and the impeller of the pump under various operation conditions are obtained. The results show that the cavitation developments on the impeller and on the inducer with the flow rates are reverse, while the development of the inlet pressure on the inducer and the impeller is the same. Cavitation on the impeller increases with the increase of flow rates, and it extends to the near passages with rotating, while cavitation on the inducer is more complex than that on the impeller. Cavitation at the inlet of the inducer decreases with the increase of flow rates, while cavitation at the outlet of the inducer is opposite. The results also show that cavitation development on the impeller and on the inducer with the inlet pressure is the same. Cavitation both decreases with the increase of the inlet pressure at the same flow rate. Furthermore, asymmetric cavitation on the impeller and on the inducer is both observed. And the asymmetric degree of cavitation on the impeller is higher than that on the inducer.