挑坎型掺气减蚀设施过流掺气特性研究

采用一维激光测速系统，对掺气减蚀工程中常用的直线型挑坎的流场特性进行试验研究．通过测量挑坎上及空腔区水流的流速分布及紊动特性，探讨通气量与紊动强度的关系．同时在深入研究流场特性和掺气机理的基础上，通过分析影响掺气的因素，从理论上探求临界掺气流速的计算，重点分析挑坎型掺气过流在空腔负压较大的情况下，临界掺气条件的理论预测，并通过试验资料验证了该计算方法．在此基础上，还进一步研究了掺气量的计算公式及其变化规律．

Air Entrainment Characteristics of Flow over an Aerator Device with Ramp

In this paper, one-dimensional laser Doppler Anemometer has been used to study the flow field of flows over a linear ramp, which is often applied to reduce cavitation erosion. By measuring the flow velocity distribution and turbulent characteristics over the ramp and in the cavity, the relation between quantity of entrained air and turbulent intensity was investigated. Based on knowledge of flow field and entrainment mechanism, factors affecting entrainment were analysed. The critical velocity of entrainment was deduced the rectically, then it was mainly applied to flows over ramp under a high negative pressure in cavity, the LDA measurements verified this method. From this, further study on calculation methods of entrained air quantity and its variation laws was carried out.