Study on the Pendulum Characteristic of Nature Convection in Dimensional Enclosure

2012 ◽  
Vol 542-543 ◽  
pp. 1120-1123
Author(s):  
Chuan Zhi Mei ◽  
Lin Hua Piao ◽  
Quan Gang Yu ◽  
Bao Li Zhang ◽  
Xia Ding ◽  
...  
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Source ◽  
Tilt Angle ◽  
Model Building ◽  
Two Dimensional ◽  
Point Heat Source ◽  
Equation Solving ◽  
Tilt Sensor ◽  
Characteristic 2

In this paper, the pendulum characteristic of nature convection gas in dimensional enclosure is analyzed by FEM. Using ANSYS-FLOTRAN CFD program, the stream field and the temperature field caused by the point heat source, when the two-dimensional enclosure is inclined, has been obtained by a series of procedure, such as model building, meshing, loads applying and equation solving. The results are as follow: (1)Under the buoyancy lift affecting, the direction of nature convection gas always keeps the vertical upward in two-dimensional enclosure, nature convection gas has the pendulum characteristic. (2)When the dimensional enclosure is inclined, temperature distribution at the several points in dimensional enclosure will change with the tilt angle. The pendulum characteristic can be utilized to measure the tilt angle by the gas pendulum tilt sensor.

FEM Analysis of the Pendulum Characteristic of Nature Convection in Dimensional Enclosure

2012 ◽  
Vol 505 ◽  
pp. 195-198
Author(s):  
Quan Gang Yu ◽  
Lin Hua Piao ◽  
Xing Wang
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Tilt Angle ◽  
Model Building ◽  
Fem Analysis ◽  
Two Dimensional ◽  
Point Heat Source ◽  
Equation Solving ◽  
Tilt Sensor ◽  
Characteristic 2

In this paper, the pendulum characteristic of nature convection gas in dimensional enclosure is analyzed by FEM. Using ANSYS-FLOTRAN CFD program, the stream field and the temperature field caused by the point heat source, when the two-dimensional enclosure is inclined, has been obtained by a series of procedure, such as model building, meshing, loads applying and equation solving. The results are as follow: (1)Under the buoyancy lift affecting, the direction of nature convection gas always keeps the vertical upward in two-dimensional enclosure, nature convection gas has the pendulum characteristic. (2)When the dimensional enclosure is inclined, temperature distribution at the several points in dimensional enclosure will change with the tilt angle. The pendulum characteristic can be utilized to measure the tilt angle by the gas pendulum tilt sensor.

Study of the Gas Pendulum Characteristic of Enclosure with Small Size

2014 ◽  
Vol 635-637 ◽  
pp. 782-785
Author(s):  
L.H. Piao ◽  
Qi Rui Yang ◽  
J.J. Zhao
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Heat Source ◽  
Temperature Difference ◽  
Tilt Angle ◽  
Temperature Fields ◽  
Two Dimensional ◽  
Point Heat Source ◽  
Element Analysis ◽  
Characteristic 2

The flow and temperature fields caused by point heat source were obtained with the method of FEA (finite element analysis), and the pendulum characteristic of nature convection gas in two-dimensional enclosure with small size was validated and explained. The results are as follow: (1) Whether in horizontal status or in tilting status, under the function of buoyancy lift, the direction of nature convection gas always keeps vertical upwards in two-dimensional enclosure, and it has the pendulum characteristic.(2)The temperatures of two points on the same isotherm are no longer equal. When the tilt angle is 10°, the temperature difference is 20K; when the tilt angle is 20°, the temperature difference is 40K.The tilt angle can be measured by using this characteristic of MEMS airflow level posture sensor.

scholarly journals Temperature distribution of an infinite slab under point heat source

2014 ◽  
Vol 18 (5) ◽  
pp. 1597-1601 ◽  
Author(s):  
Zhao-Chun Wu ◽  
Dao-Lai Cheng
Keyword(s):  
Temperature Field ◽  
Thermal Properties ◽  
Temperature Distribution ◽  
Heat Source ◽  
Manufacturing Processes ◽  
Point Heat Source ◽  
Treatment Processes ◽  
Measuring Devices ◽  
Infinite Slab ◽  
Continuous Point

The temperature field in an infinite slab under an instantaneous or continuous point heat source is studied numerically. The numerical results reveal the temperature distribution and its change regularity, which are significant for the temperature control encountered in many practical manufacturing processes, such as the laser treatment processes on the surface of films, welding and cutting, and even the design of measuring devices for thermal properties of material.

An analytical solution of a two-dimensional temperature field in a hollow cylinder under a time periodic boundary condition using Fourier series

2009 ◽  
Vol 223 (8) ◽  
pp. 1889-1901 ◽  
Author(s):  
G Atefi ◽  
M A Abdous ◽  
A Ganjehkaviri ◽  
N Moalemi
Keyword(s):  
Boundary Condition ◽  
Temperature Field ◽  
Fourier Series ◽  
Temperature Distribution ◽  
Analytical Solution ◽  
Hollow Cylinder ◽  
Periodic Boundary Condition ◽  
Periodic Boundary ◽  
Separation Of Variables ◽  
Two Dimensional

The objective of this article is to derive an analytical solution for a two-dimensional temperature field in a hollow cylinder, which is subjected to a periodic boundary condition at the outer surface, while the inner surface is insulated. The material is assumed to be homogeneous and isotropic with time-independent thermal properties. Because of the time-dependent term in the boundary condition, Duhamel's theorem is used to solve the problem for a periodic boundary condition. The periodic boundary condition is decomposed using the Fourier series. This condition is simulated with harmonic oscillation; however, there are some differences with the real situation. To solve this problem, first of all the boundary condition is assumed to be steady. By applying the method of separation of variables, the temperature distribution in a hollow cylinder can be obtained. Then, the boundary condition is assumed to be transient. In both these cases, the solutions are separately calculated. By using Duhamel's theorem, the temperature distribution field in a hollow cylinder is obtained. The final result is plotted with respect to the Biot and Fourier numbers. There is good agreement between the results of the proposed method and those reported by others for this geometry under a simple harmonic boundary condition.

Finite Element Analysis of Nozzle Position on Nozzle Array Fluidic Gyroscope Performance

2013 ◽  
Vol 753-755 ◽  
pp. 2713-2716
Author(s):  
Jing Bo Chen ◽  
Lin Hua Piao ◽  
Zhi Wei Fan
Keyword(s):  
Finite Element ◽  
Sensitive Element ◽  
Model Building ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Element Analysis ◽  
Equation Solving ◽  
Element Simulation ◽  
Nozzle Position ◽  
Convergence Trend

In this paper, research the influence on position of vice nozzle in the sensitive element of nozzle array fluidic gyroscope. Using ANSYS-FLOTRAN CFD software, the finite element simulation is conducted by a series of procedures, such as two-dimensional model building of fluidic gyroscope, meshing, loads applying and equation solving. The two dimensional airflow distributions of different distances between vice nozzle and main nozzle in sensitive element of nozzle array fluidic gyroscope are calculated. The results show that, the distance between vice nozzle and main nozzle l=1.1mm, velocity of airflow at the outlet VSUM=0.71455m/s, and it is 47.6% of the velocity at the inlet, which increases by 1.75% than the distance l=0.5mm. The larger distance between vice nozzle and main nozzle has better convergence trend, it reduces the decay which causes by the airflow propagation, promotes airflow movement and increases temperatures changes without any vortex increase in sensitive cavity, so it can improve the sensitive of fluidic gyroscope.

Optimal Design of Sensitive Structure in Gas Pendulum Tilt Sensor

2014 ◽  
Vol 716-717 ◽  
pp. 1051-1054
Author(s):  
Yong Hong Zheng ◽  
Shi Liu Peng ◽  
Hong Wei Wang
Keyword(s):  
Temperature Field ◽  
Optimal Design ◽  
Heat Source ◽  
Horizontal Distance ◽  
Ansys Software ◽  
Simulated Temperature ◽  
Sensitive Factor ◽  
Tilt Sensor ◽  
Sensitive Structure

Optimal design of sensitive structure in gas pendulum tilt sensor was discussed. Using ANSYS software, fluid fields produced by heat source of the sensor in center were simulated. According simulated temperature field which is the key sensitive factor of the tilt sensor, optimal design of sensitive structure was discussed further. The results show that sensitivity of sensor is better when the distance between sensor wire and heat source is 0.2 R or 0.3R (R is radius of chamber). In respect to vertical place, experiment and theory show sensor has better sensitivity and linearity when installing angle is 60 ̊ while the horizontal distance between sensor wire and heat source is 0.3R.

Flow Similarity Applied in Convection-Based Tilt Sensor

2007 ◽  
Author(s):  
Shiliu Peng ◽  
Yonghong Zheng
Keyword(s):  
Heat Source ◽  
Temperature Difference ◽  
Tilt Angle ◽  
Temperature Drift ◽  
Perpendicular Line ◽  
Environment Temperature ◽  
Tilt Sensor ◽  
Line Cross ◽  
Flow Similarity ◽  
Tilt Sensors

The environment temperature has inevitable effects on property of the convection-based tilt sensors. It not only redefines the application, but also prevents the improvement of the sensor performance. Numerical simulation of the fluid flow in the chamber of a sensor was performed and the influence of the environment temperature was studied in this paper. At zero tilt angle, the temperature distribution along the perpendicular line cross the heat source at various environment temperatures was presented. It was found that the flow varied dramatically at different environment temperatures, which would cause the output signal vary accordingly, even when the tilt angle was kept at a constant, because this device works by sensing the change of flow. At the same condition, we present the numerical results when the temperature difference across the heat source and the environment was kept at the same, in those results, it was found that the temperature difference at every point along the perpendicular line cross the heat source keep the same, this result confirms the similarity principle of nature convection. Second, A method of eliminating environment temperature infect on property of convection-based tilt sensor, which is based on the theory of flow similarity, is proposed. It was found that a thermal transistance can be piped on the circuit of heat source to compensate the temperature of the heat source. A compensative circuit was specially designed which can keep flow similarity by changing heat source temperature in order to eliminate the influence of environment temperature. The experiment results show that above 70% temperature drift can be eliminated by this compensative circuit.

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