Thermal modeling of a MEMS for determination of fluid and flow characteristics

2001 ◽  
Author(s):  
Nicolae Damean ◽  
Paul P. L. Regtien
Keyword(s):  
Thermal Modeling ◽  
Flow Characteristics

Determination of Flow Characteristics and Turbulent Heat Transfer in a Ribbed Roughened Square Duct, Part 2: Numerical Simulations

2011 ◽  
Vol 110-116 ◽  
pp. 2364-2369
Author(s):  
Amin Etminan ◽  
H. Jafarizadeh ◽  
M. Moosavi ◽  
K. Akramian
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Turbulent Heat Transfer ◽  
Turbulent Heat ◽  
Square Duct ◽  
Optimized Model ◽  
Rsm Model

In the part 1 of this research, some useful turbulence models presented. In that part advantages of those turbulence models has been gathered. In the next, numerical details and procedure of solution are presented in details. By use of different turbulence models, it has been found that Spallart-Allmaras predicted the lowest value of heat transfer coefficient; in contrast, RSM1 has projected the more considerable results compared with other models; besides, it has been proven that the two-equation models prominently taken lesser time than RSM model. Eventually, the RNG2 model has been introduced as the optimized model of this research; moreover.

Experimental Verification of the Improvements Achieved by a New LP-Blade Design in a Steam Turbine

1992 ◽  
Author(s):  
H. Stetter ◽  
G. Eyb ◽  
C. Zimmermann ◽  
H.-G. Hosenfeld
Keyword(s):  
Steam Turbine ◽  
Entire Range ◽  
Flow Characteristics ◽  
Radial Pressure ◽  
Blade Design ◽  
Steam Turbines ◽  
Guide Vanes ◽  
Last Stage ◽  
The University

In order to verify the improvements in the understanding of the flow in turbomachinery, extensive investigations were carried out at the LP-steam turbine at the University of Stuttgart. This paper initially focuses on the specific measuring technique in steam turbines with respect to problems of condensation. The stator wakes, noticeable in all measuring planes of the stage, require the determination of the flow vector over a large portion of the cross-section to obtain representative values. The application of a newly designed last stage for LP-steam turbines, which is characterized by curved guide-vanes, led to considerable improvements of the flow over the entire range of operation. The results gained by measurements on that stage are compared to former measurements on a stage version with straight guide-vanes. A significant change of flow characteristics over the blade span can be noticed. Particularly, the flow in the hub region was improved by balancing the radial pressure distribution.

Determination of Subsurface Flow Characteristics for the Installation of Groundwater Samplers

2015 ◽  
pp. 383-393 ◽  
Author(s):  
Wayne P. Dulaney ◽  
T. J. Gish ◽  
C. S. T. Daughtry ◽  
J. A. Doolittle ◽  
P. T. Miller ◽  
...  
Keyword(s):  
Subsurface Flow ◽  
Flow Characteristics

scholarly journals Theoretical Rotordynamic Coefficients of Labyrinth Gas Seals: a Parametric Study on a Bulk Model

1999 ◽  
Vol 5 (1) ◽  
pp. 67-76 ◽  
Author(s):  
Paola Forte ◽  
Fabio Latini
Keyword(s):  
Flow Characteristics ◽  
Perturbation Approach ◽  
Rotordynamic Coefficients ◽  
Volume Model ◽  
Complex Models ◽  
Gas Seals ◽  
Bulk Model ◽  
Stiffness And Damping ◽  
Good Agreement

To date, available mathematical bulk models for the determination of linearized rotordynamic coefficients of labyrinth gas seals yield results which are not always in good agreement with the experimental ones. The object of this work is to discuss the limits of these models and to point out possible improvements and aspects that need further investigation.After a study of the steady flow characteristics with an FEM code, a parametric computer program, based on a known two-volume model, has been developed. A perturbation approach has been applied to the governing equations of the bulk model to calculate the stiffness and damping coefficients. Predicted coefficients are compared to the results of an earlier one-volume model.The model has also been tested with different expressions of the axial velocities in the two volumes and different laws for leakage and shear stress. The theoretical results are compared to the published experimental ones, pointing out the small effect of the various parameters in improving the correlation and the need of more complex models.

scholarly journals Determination of Flow Characteristics in Technological Processes with Controlled Pressure

2020 ◽  
Vol 11 (3) ◽  
pp. 204-211
Author(s):  
T. Reader ◽  
V. A. Tenenev ◽  
A. A. Chernova
Keyword(s):  
Mathematical Model ◽  
Differential Equations ◽  
Flow Rate ◽  
Gas Flow ◽  
Safety Valve ◽  
Flow Characteristics ◽  
Pressure Change ◽  
Time Curve ◽  
Mass Rate

Assessment of the environmental and economic performance of a safety valve requires information about the flow of the substance through the valve when it is actuated. The goal of this paper was to determine the flow rate of the discharged substance and the mass flow rate of the substance entering the safety valve when it is actuated.Proposed a mathematical model to describe the processes occurring in the valve. The model includes a system of differential equations describing the physical laws of conservation in the internal volume of the valve and differential equations, which link the value of gas flow through the valve with the pressure and the amount of movement of the shut-off disk. Used a modified method by S.K. Godunov to solve gasdynamic equations.Established that the determination of the flow and power characteristics of the valve requires the preliminary construction of a mathematical model of the safety valve operation. Based on this, proposed a method for determining the flow rate of the discharged substance and the mass rate of the substance entering the safety valve when it is actuated.Obtained the flow characteristics of the valves under review and the dynamics of movement of the shutoff disc of the valve, as well as the dependence of the pressure change on the opening time of the valve. Comparison of the calculated values with available experimental data gives good agreement of results (no more than 5.6 % for a gas flow rate, under 10 % for the movement of the valve and change the arrival of gas in time using the standard deviation function of the flow characteristics of 0.6 %), confirms the correctness of the defined mathematical model, used numerical schemes and algorithms, as well as the proposed method and recoverability of the arrival of gas in a pressure–time curve.

scholarly journals DETERMINATION OF THE FLOW CHARACTERISTICS IN A PIPE WITH TORTUOSITY

2016 ◽  
Vol 32 (4) ◽  
Author(s):  
А. О. Борисюк ◽  
Я. А. Борисюк
Keyword(s):  
Flow Characteristics
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