ABSTRACT

Phase Doppler measurement devices have established themselves as an alternative to laser diffraction-based measurements for recording spray drop size distributions. In addition, phase Doppler devices also provide droplet velocities and volume flux. One limitation of the phase Doppler systems that is not discussed often in the literature is their sensitivity to the amplification voltage used on the photo-multiplier tube (PMT) detector. The correct value of voltage to use depends on the spray density, and so a calibration must be made for each spray by mechanically measuring the flux at a point in the spray. Phase Doppler output parameters (drop sizes, velocities, validation rate, and derived parameters) were measured as a function of voltage in a fixed location in a water spray. The measurements of volume median diameter were not as sensitive to the voltage setting as the volume flux measurements, which may be why the issue of voltage sensitivity is not discussed much in the literature. The contributions of the current work are: for the first time, measurements of sensitivity of D_V05 and LWC to PMT voltage settings in PDI are reported, as well as the details of the different validation parameters instead of only the overall validation rate.

摘要

相位多普勒测量设备已经确立了自己的地位，可以替代基于激光衍射的测量方式来记录雾滴尺寸分布。另外，相位多普勒装置还提供液滴速度和体积通量。相位多普勒系统的一个局限性是文献对光电倍增管（PMT）检测器上使用的放大电压的敏感性，在文献中没有经常讨论。所使用的正确电压值取决于喷雾密度，因此必须通过机械测量喷雾中某一点的通量来对每种喷雾进行校准。测量水喷雾中固定位置的相位多普勒输出参数（液滴大小，速度，验证率和派生参数）与电压的关系。体积中值直径的测量对电压设置的敏感性不如体积通量测量，这可能就是为什么电压敏感性问题在文献中未作过多讨论的原因。当前工作的贡献是：首次测量了传感器的灵敏度。报告了PDI中的D _{V 05}和LWC到PMT的电压设置，以及不同验证参数的详细信息，而不仅仅是总验证率。