等压混合引射器设计与实验研究

 采用1维处理方法，建立了便于设计人员使用的等压混合引射器性能计算分析与工程设计方法，并详细分析了等压混合引射器各主要参数对性能的影响。该分析方法基于气体焓的变化，因此可应用于各种引射气体与被引射气体。为了控制尺寸，还首次将多喷嘴引射方式与等压混合结合起来。实验结果验证了等压混合引射器性能计算分析与工程设计方法的可靠性以及多喷嘴引射方式应用于等压混合引射器的可行性。     

Experimental Study on Physical Mechanism of Drag Reduction of Hydrophobic Materials in Laminar Flow

We experimentally study the physical mechanism of the drag reduction of hydrophobic materials in the macroscopic scale. The experiment includes the drag and velocity measurements of laminar boundary layer flow over flat plates, and the observation of air bubbles on the surfaces. The plate surfaces have different wetting and roughness properties. In the drag measurements, the plates with bubbles on the surfaces lead to drag reduction, but not for those without bubbles. Velocity measurement confirms that the flow is laminar and gives apparent fluid slip on the plate wall with bubbles. In observation, air bubbles in macroscopic size emerge and enlarge on hydrophobic surfaces but not on hydrophilic surfaces. Therefore, the drag reduction of hydrophobic materials is explained by the generation of air bubbles of macroscopic size that cause the apparent velocity slip.