High-Volume Low-Turbulence Inlet for Aerosol Sampling from Aircraft

9713408 Seebaugh在这个项目中，将设计、建造一种用于NCARC-130型飞机的大流量低湍流气雾剂进气口，并展示其性能。该进气口将能够对空气动力学直径高达10微米的超微米气溶胶进行采样。需要一个低湍流度的进气口，以最大限度地减少进气口壁上的颗粒损失。进气扩散器段的边界层吸力将被用作湍流缓解技术。拟建的进气口的流量为每分钟200-400升，以提供大流量的叶栅冲击器系统。该项目还将有可能为其他更一般的气溶胶采样应用设计类似的进气口，因为目标流速高于许多其他要求。将建立一个参考进气口(没有边界层吸力)，为评估湍流减振技术提供基线。它将使用常规设计的圆锥形扩散器来产生20倍的减速(扩散器入口与出口速度之比)。参考进气口将在与C-130飞机的飞行包线相对应的一系列条件下进行测试，以确定扩散器出口的流动特性(时间平均速度和湍流强度)。将建造一个低湍流度的进气口(使用边界层吸力)，作为在先前NSF项目中成功演示的进气口的放大版本。扩散器部分将由铸造和烧结的多孔塑料制造。大约60%-80%的进气流量将被吸除，以达到所需的减速20倍。第二年，将在实验室对低湍流进气进行表征和优化。将为C-130飞机设计和建造飞行系统。通过对扩散器出口流动特性的测量和对扩散器内壁和壁面流动的计算流体力学分析，可以确定进口内的流动应力线和大颗粒的惯性增强。惯性增强也将通过在几个选定的测试条件下使用光学颗粒计数器或空气动力学颗粒测量仪在运行过程中测量进气口外和扩散器出口处颗粒的尺寸分布来确定。第三年工作的目标是对进气口进行飞行测试，并为进气口系统的用户提供操作援助。

9713408 Seebaugh In this project, a high-volume low-turbulence aerosol inlet for use on the NCAR C-130 aircraft will be designed, constructed, and its performance demonstrated. This inlet will enable the sampling of supermicron aerosols up to 10 micrometer aerodynamic diameter. A low turbulence inlet is required to minimize particle losses to the inlet walls. Boundary layer suction in the diffuser section of the inlet will be used as the turbulence mitigation technique. The proposed inlet will have a flow rate of 200-400 liters per minute to supply a high-volume cascade impactor system. This project will also make it possible to design similar inlets for other more general aerosol sampling applications since the target flow rate is higher than many other requirements. A reference inlet (without boundary layer suction) will be built to provide a baseline for evaluation of the turbulence reduction techniques. It will use a conical diffuser of conventional design to produce a velocity reduction (ratio of diffuser entrance to exit velocity) of a factor of 20. The reference inlet will be tested over a range of conditions corresponding to the flight envelope of the C-130 aircraft to determine the flow characteristics (time mean velocity and turbulence intensity) at the diffuser exit. A low turbulence inlet (using boundary layer suction) will be built as an enlarged version of the inlet successfully demonstrated during prior NSF project. The diffuser section will be manufactured from a cast and sintered porous plastic. About 60-80% of the inlet flow will be removed by suction to achieve the desired velocity reduction of a factor of 20. In the second year, the low turbulence inlet will be characterized and optimized in the laboratory. A flight system for the C-130 aircraft will be designed and constructed. By combining measurements of the flow characteristics at the diffuser exit and computational fluid dynamics analysis of the flow within and through the walls of the diffuser, the flow stre amlines inside the inlet and the inertial enhancement for large particles will be determined. The inertial enhancement will also be determined experimentally by measuring the size distribution of particles outside the inlet and at the diffuser exit during operation using either an optical particle counter or an aerodynamic particle sizer for several selected test conditions. The objectives of the third year effort are flight testing of the inlet and operational assistance for users of the inlet system.