Development of Highly Precise Micro Wall Sensor and Its Advanced Evaluation System

本研究项目的总体目标是开发先进的微传感风洞评价系统以及精确的壁面流量传感器。获得了先进的微器件评价体系。利用微粒子图像测速系统搭建了微传感风洞，以了解微器件的性能。为了提高传感器的时间响应性，我们还设计了一种新型的可以检测壁面剪应力和流动方向的微流量传感器。在新型的微传感器结构中，两个传感元件排列在硅片上，并由于元件的自加热而用作加热器，以实现更高的频率响应和小型化。流量传感元件是制作在硅片上的热敏薄膜电阻。微流量传感器的原理是基于受热阻力元件向周围流体流动的对流换热。通过对二维低雷诺数流动的数值模拟，确定了传感器的最优结构。在可行性研究中发现，尺寸缩小30%的微流量传感器具有更高的灵敏度。结果表明，本系统可作为低雷诺数流动微器件的有效设计与校核系统应用于工程应用。

The general goal of the present research project is to develop the advanced evaluation system in the micro sensing wind tunnel as well as the precise wall flow sensor. We obtained the advanced evaluation system of the micro devices. The micro sensing wind tunnel was constructed to clarify performance of the micro devices by using the micro Particle Image Velocimetry system. We also designed a new type of the micro flow sensor which can detect the wall shear stress and the flow direction in order to improve the time response of the sensor. In the new type of the micro sensor configuration, the two sensing elements are arrayed on the silicon chip and also used as heater due to a self-heating of the elements for higher frequency response and miniaturization. The flow sensing elements are thermal sensitive thin film resistors fabricated on the silicon chip. The principle of the micro flow sensor is based on the convective heat transfer from the heated resistance elements to the surrounding fluid flow. The optimum configuration of the sensor was decided by the numerical simulation of a two-dimensional low Reynolds number flow including the heat conduction within the chip base. The proposed micro flow sensor with 30% reduction in size is found to have higher sensitivity in the feasibility study. As a result, the present system can be employed in the engineering application as the effective design and check system for the micro devices in the low-Reynolds number flow