Papers by Keyword: Flow Sensor

Abstract: The main problems of the gas flow meters are the improvement of the sensitivity and velocity range. In this paper thermoresistive membrane gas flow sensor is considered. The sensor is based on the calorimetric principle of operation and developed for the thermal gas flow meters. Special streamlined body was used to improve sensor’s characteristics. It is shown that streamlined body raises sensitivity by 2 times and improves velocity range of the sensor.

Abstract: The dome-shaped membrane was designed for the fluidic based flow sensor for the underwater sensing. It has the diameter of 5mm and thickness within 0.2mm. The simple fabrication process for the dome shaped structure was demonstrated using casting and molding processes. The effect of the fabrication process was investigated by measuring the thickness of the dome-shaped membrane for different sample. For the performance analysis, the actual shape which was the same with the fabricated shaped was simulated and compared with the ideal shape using finite element analysis for the same input flow rate. The membrane sensitivity of the actual shape decreased from 163.4 μm/ms^-1 to 133.33 μm/ms^-1 compared to the ideal shape based on the displacement of the membrane over input fluid velocity.

Abstract: The hot-film flow sensors accurately measure the intake flow of engine. The air flow in the engine intake manifold is typical unsteady flow whose flow velocity changes remarkably. Therefore, the flow sensor should have a faster dynamic response characteristic. A thermosetting coupling model of a hot-film sensor was established based on CFD which is used to simulate dynamic response characteristics; the temperature field of the hot-film flow sensor probe was simulated. In addition, the dynamic response characteristics of the sensor simulated using the step pulse, and tested the dynamic response characteristics based on flow test equipment.

Abstract: To overcome the deficiency of the existing billing modes of hot water system, such as based on time or flow signal alone, in this paper a billing method which integrates several signals is presented. The detected flow, temperature and time signals are synthesized to determine the billing function of hot water. Due to the different seasons and regions, an adjustment factor is designed to make the billing function more flexible and intelligent. This may make users’ expenses reasonable, and it also considers the loss of the managers. This proposed billing mode is successfully implemented in the hardware system controlled by Single-chip Microcomputer.

Abstract: The paper introduces an electrical design to dilute heavy crude oil. The design is based on the feedback principle and includes detection part, control part and actuator part. The practice proves the design is reliable and accurate to realize the proportion between the crude oil flow and dilution liquid flow.

Abstract: In this paper, the diaphragms Mechanical property of Hot-film air flow sensor is studied on the base of proposition of double-sided convection heat air flow sensor. This diaphragm consists of barrier layer, support layer and passivation layer. For Hot-film air flow sensor, the Diaphragms Mechanical property is mainly up to the support layer, and the support layer is composed of Si₃N₄. In this research, four types of air flow sensors with different thickness of the support layer is prepared and tested at different air flow velocity. On the same time, the stress analysis of the sensor diaphragm is simulated at the flow rate of 5m/s by the finite element software. A conclusion can be drawn that the thickness of support layer can not be less than 1000nm, when the air flow velocity is more than 5m/s.

Abstract: In recent years, the development of fuel cells has proceeded rapidly, and so the reforming of methanol to produce hydrogen has become a serious problem. Supplying hydrogen from a micro methanol reformer to fuel cells is an important topic. The structure of a micro flow channel must support the transfer of external heat to the reform reaction, facilitating the diffusion of methanol vapor into the catalyst layer, increasing the rate of transfer of hydrogen. In this investigation, the micro-electro-mechanical systems (MEMS) technique is utilized to fabricate micro pressure, temperature and flow sensors. Polyimide film (PI) exhibits high temperature resistance and stress corrosion resistance, and is adopted herein as a flexible substrate. In future work, such micro sensors will be embedded in a micro methanol reformer for in-situ diagnosis.

Abstract: A flow sensor for liquids, based on the principle of fluid-structure heat transfer is presented. The heater and thermistor are integrated and wrapped together as a detector and heat source, allowing heat exchange between the sensor and the fluid. Through numerical simulation, the temperature distribution of the sensor was investigated, under conditions of various flow velocities. The process of turbulent heat transfer in the flow pipe was simulated, the temperature distribution in the sensor was analyzed and compared under different temperature and velocity of the fluid, and the corresponding measuring ranges were determined. The flow detection circuit is designed and the results of water flow velocity tests in the range of (0.01–1)m/s are presented.

Abstract: In this work, several millimeter sized micro whistles have been tested as potential frequency analog gas flow sensors. The characteristic curves of the whistles were systematically investigated as a function of geometrical dimensions, the kind of gas applied, and temperature. Both a micro¬phone and a PVDF foil were employed to record the frequencies. The relation be¬tween oscillation frequency and volume flow rate only shows a weak function of fluid properties and temperature. At a given flow rate, the difference of argon and nitrogen is 120 Hz on average, which is corresponding to 1.4 %. For air flow at a given flow rate, frequency rises approximately 380 Hz (2.73 %) per 10 °C. This kind of micro whistle could be employed as gas flow sensor which is insensitive to fluid properties.

Abstract: The heat metering system is one of the key facilities to reform the heating systems of city and to charge according to heat quantity consumption. The design of heat metering system based on mcs-51 includes two sections--hardware and software. The hardware section is composed of flow sensor, temperature sensor and single-chip microcontroller (SCM for short). The system can calculate heat quantity intelligently, so the users pay the actual heat quantity consumption.