Research On MEMS-Based Thermal Flow Measuring Method And System

On the base of analyzing the development and trend of the thermal flowmeter technology, this paper researched on thermal flowmeter detection methods and system based on Micro-Electro-Mechanical System (MEMS). The mathematical model of the thermal flowmeter under constant power and constant temperature are used to analyze its response characteristic, sensitivity and measuring error. Then, a frame-model of flow monitoring system based on LabVIEW and multi-agent technology is introduced and its prototypes of the communication system and operational mechanism of software space are designed.Chapter one outlines the research significance of flow monitoring, and introduces the main classification methods and development trend of flow inspection technology, presents the three types of thermal mass flow detection and their general situations, and analyzes the present application situation and development trend of flow remote monitoring system. At last, the main content and general structure are presented.Chapter two uses heat transfer theory to analyze the principle of thermotransfer micro flowmeter and the heat transfer differential equation is established and solved with the different boundary conditions under constant power and constant temperature. The resulting models are validated by the ANSYS large finite element software and its error sources are analyzed.Chapter three uses the mathematical model to analyze the response characteristic, sensitivity of the flowmeter, the effect of structure dimension and its mismachining tolerance are also presented. Lastly, the micro flow sensor is briefly designed.Chapter four introductions the general structure of flow monitoring system, shows the main issues in recent development. With the use of GPRS, virtual instrument and multi-agent technology, a frame-model of flow monitoring system is brought forward based on the concept of agent and space.Chapter five designs the communication system and operational mechanism of the system as the key tasks in the realization of the software space of the frame-model. At last, a method of system configuration based on the concept of configuration is propounded.In the end, in the chapter six, all of the work in this dissertation is summarized, and the future researches are prospected.