scholarly journals Fabrication and Evaluation of a Flexible MEMS-Based Microthermal Flow Sensor

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 8153
Author(s):  
Myoung-Ock Cho ◽  
Woojin Jang ◽  
Si-Hyung Lim
Keyword(s):  
Flow Velocity ◽  
Output Voltage ◽  
Gas Flow ◽  
Fluid Velocity ◽  
Wheatstone Bridge ◽  
Polyimide Film ◽  
Flow Sensor ◽  
Healthcare Applications ◽  
Labview Software ◽  
Liquid Flows

Based on the results of computational fluid dynamics simulations, this study designed and fabricated a flexible thermal-type micro flow sensor comprising one microheater and two thermistors using a micro-electromechanical system (MEMS) process on a flexible polyimide film. The thermistors were connected to a Wheatstone bridge circuit, and the resistance difference between the thermistors resulting from the generation of a flow was converted into an output voltage signal using LabVIEW software. A mini tube flow test was conducted to demonstrate the sensor’s detection of fluid velocity in gas and liquid flows. A good correlation was found between the experimental results and the simulation data. However, the results for the gas and liquid flows differed in that for gas, the output voltage increased with the fluid’s velocity and decreased against the liquid’s flow velocity. This study’s MEMS-based flexible microthermal flow sensor achieved a resolution of 1.1 cm/s in a liquid flow and 0.64 cm/s in a gas flow, respectively, within a fluid flow velocity range of 0–40 cm/s. The sensor is suitable for many applications; however, with some adaptations to its electrical packaging, it will be particularly suitable for detecting biosignals in healthcare applications, including measuring respiration and body fluids.

Self-Oscillating Microcantilever Piezoresistive Flow Sensor

2006 ◽  
Vol 326-328 ◽  
pp. 1347-1350
Author(s):  
Jeung Sang Go ◽  
Bo Sung Shin ◽  
Jong Soo Ko
Keyword(s):  
Gas Flow ◽  
Printed Circuit Board ◽  
Fluid Velocity ◽  
Flow Sensor ◽  
Circuit Board ◽  
Flow Induced Vibration ◽  
Peak Voltage ◽  
New Approach ◽  
Inlet Velocity ◽  
Microfabrication Technology

This article presents a new approach to measure the fluid velocity using the flow-induced vibration of a microcantilever. The gas flow sensor was fabricated using the microfabrication technology and mounted on a printed circuit board for experimental evaluation. For signal processing, a Wheastone bridge circuit was prepared. The experimental measurement of the fluid velocity was performed in the wind tunnel. The flow-induced vibration of the microcantilever was firstly visualized. Based on the power spectrum analysis, the vibrating frequency was constant at 1.173 kHz, independently of the inlet velocity. It is completely different from the conventional flow-induced vibration proportional to the inlet velocity. The peak-to-peak voltage outputs corresponding to the air velocities of 3, 4, 5 and 6 m/s were measured.

Development of a Gas Flow Sensor Based on FS5 Hot-Film Probe

2014 ◽  
Vol 568-570 ◽  
pp. 537-541
Author(s):  
Lei Yang ◽  
Jia Qiang Yang
Keyword(s):  
High Precision ◽  
Output Voltage ◽  
Gas Flow ◽  
Characteristic Curve ◽  
Measurement Data ◽  
Least Square Method ◽  
Industrial Applications ◽  
Least Square ◽  
Flow Sensor ◽  
Hot Film

On the basis of thermal measuring method, a hot-film gas flow sensor is proposed. Its sensitive element is a FS5 probe, which is integrated with measuring resistance and temperature compensating resistance inside. In order to achieve temperature compensation, the main measuring circuit is designed. Considering minimizing errors in this circuit, the temperature correcting circuit is added to further modify output voltage. By fitting measurement data of gas flow and the final output voltage with least square method, an operating characteristic curve is obtained as well as its 4th order polynomial. Under equivalent conditions, the proposed sensor, a high-precision standard sensor and an industrial sensor are experimented upon and the contrast analysis of their measurement results is given. The experimental results prove that the proposed sensor has high precision with measurement error less than 3%. Therefore the proposed sensor is feasible for industrial applications.

scholarly journals Modeling of three-dimensional exciplex pumped fluid Cs vapor laser with transverse and longitudinal gas flow

2021 ◽  
Vol 9 ◽  
Author(s):  
Chenyi Su ◽  
Xingqi Xu ◽  
Jinghua Huang ◽  
Bailiang Pan
Keyword(s):  
Wall Temperature ◽  
Laser Power ◽  
Gas Flow ◽  
Particle Density ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Heat Accumulation ◽  
Vapor Laser ◽  
Output Laser Power ◽  
Output Laser

Abstract Considering the thermodynamical fluid mechanics in the gain medium and laser kinetic processes, a three-dimensional theoretical model of an exciplex-pumped Cs vapor laser with longitudinal and transverse gas flow is established. The slope efficiency of laser calculated by the model shows good agreement with the experimental data. The comprehensive three-dimensional distribution of temperature and particle density of Cs is depicted. The influence of pump intensity, wall temperature, and fluid velocity on the laser output performance is also simulated and analyzed in detail, suggesting that a higher wall temperature can guarantee a higher output laser power while causing a more significant heat accumulation in the cell. Compared with longitudinal gas flow, the transverse flow can improve the output laser power by effectively removing the generated heat accumulation and alleviating the temperature gradient in the cell.

Numerical Analysis of Flow Fields and Temperature Fields in a Regenerative Heating Furnace for Steel Pipes

2018 ◽  
Vol 10 (3) ◽  
Author(s):  
Yi Han ◽  
Feng Liu ◽  
Xin Ran
Keyword(s):  
Temperature Field ◽  
Flow Field ◽  
Flow Velocity ◽  
Gas Flow ◽  
Flow Fields ◽  
Heating Furnace ◽  
Temperature Fields ◽  
Turbulent Layer ◽  
Steel Pipes ◽  
Pipe Blanks

In the production process of large-diameter seamless steel pipes, the blank heating quality before roll piercing has an important effect on whether subsequently conforming piping is produced. Obtaining accurate pipe blank heating temperature fields is the basis for establishing and optimizing a seamless pipe heating schedule. In this paper, the thermal process in a regenerative heating furnace was studied using fluent software, and the distribution laws of the flow field in the furnace and of the temperature field around the pipe blanks were obtained and verified experimentally. The heating furnace for pipe blanks was analyzed from multiple perspectives, including overall flow field, flow fields at different cross sections, and overall temperature field. It was found that the changeover process of the regenerative heating furnace caused the temperature in the upper part of the furnace to fluctuate. Under the pipe blanks, the gas flow was relatively thin, and the flow velocity was relatively low, facilitating the formation of a viscous turbulent layer and thereby inhibiting heat exchange around the pipe blanks. The mutual interference between the gas flow from burners and the return gas from the furnace tail flue led to different flow velocity directions at different positions, and such interference was relatively evident in the middle part of the furnace. A temperature “layering” phenomenon occurred between the upper and lower parts of the pipe blanks. The study in this paper has some significant usefulness for in-depth exploration of the characteristics of regenerative heating furnaces for steel pipes.

The Features of Measuring the Gas Flow Velocity in Pipes by an Ultrasonic Correlation Method

2021 ◽  
Vol 67 (2) ◽  
pp. 216-221
Author(s):  
A. D. Mansfeld ◽  
G. P. Volkov ◽  
R. V. Belyaev ◽  
A. G. Sanin ◽  
P. R. Gromov ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Gas Flow ◽  
Correlation Method ◽  
Gas Flow Velocity

Researches of technological mode of operation of gas wells with a single-lift elevator at a critical speed of upper flow

2021 ◽  
pp. 97-103
Author(s):  
R.A. Gasumov ◽  
◽  
E.R. Gasumov ◽  
Keyword(s):  
Gas Flow ◽  
Operating Conditions ◽  
Physical Parameters ◽  
Gas Wells ◽  
Gas Well ◽  
Field Development ◽  
Mode Of Operation ◽  
Water Drops ◽  
Liquid Flows ◽  
Technological Mode

The article discusses the modes of movement of gas-liquid flows in relation to the operating conditions of waterlogged gas wells at a late stage of field development. Algorithms have been developed for calculating gas well operation modes based on experimental work under conditions that reproduce the actual operating conditions of flooded wells of Cenomanian gas deposits. The concept of calculating the technological mode of operation of gas wells with a single-row elevator according to the critical velocity of the upward flow is considered based on the study of the equilibrium conditions of two oppositely directed forces: the gravity of water drops directed downward and the lifting force moving water drops with a gas flow directed upward. A calculation was made according to the method of the averaged physical parameters of formation water and natural gas in the conditions of flooded Cenomanian gas wells in Western Siberia. The results of a study of the dependence of the critical flow rate of Cenomanian wells on bottomhole pressure and diameter of elevator pipes are presented.

scholarly journals Gas-liquid flows through porous media in microgravity: Packed Bed Reactor Experiment-2

2021 ◽  
Author(s):  
Brian Motil ◽  
Mahsa Taghavi ◽  
Vemuri Balakotaiah ◽  
Henry Nahra
Keyword(s):  
Gas Flow ◽  
Liquid Velocity ◽  
Space Station ◽  
Particle Diameter ◽  
Packed Bed ◽  
Packed Bed Reactor ◽  
Flow Rates ◽  
Test Conditions ◽  
Superficial Gas Velocity ◽  
Liquid Flows

Experimental results on pressure drop and gas hold-up for gas-liquid flow through packed beds obtained from a second flight on the International Space Station are presented and analyzed. It is found that the gas hold-up is a function of the bed history at low liquid and gas flow rates whereas higher gas hold-up and pressure gradients are observed for the test conditions following a liquid only pre-flow compared to the test conditions following a gas only pre-flow period. Over the range of flow rates tested, the capillary force is the dominant contributor to the pressure gradient and is found to be linear with the superficial liquid velocity but is a much weaker function of the superficial gas velocity. The capillary contribution is also a function of the particle size and varies approximately inversely with the particle diameter within the range of the test conditions.

scholarly journals METHODS OF MAINTAINING THE PROJECT LEVELS OF GAS PRODUCTION AT THE FINAL STAGE OF DEVELOPMENT OF DEPOSITS

2017 ◽  
pp. 80-83
Author(s):  
E. V. Panikarovskii ◽  
V. V. Panikarovskii
Keyword(s):  
Flow Velocity ◽  
Final Stage ◽  
Gas Flow ◽  
Gas Production ◽  
Stage Of Development ◽  
Surfactant Solutions ◽  
Gas Flow Velocity

In the case of self-kill of wells, the gas flow velocity in the lifting column is not sufficient for carrying to the surface of the liquid, accumulated in the wellbore. To remove liquid from the bottom of wells, solid and liquid surfactants are used. As a result of conducted studies of surfactant compositions, the components of surfactant solutions were chosen to remove liquid from the bottom of wells.

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