THERMALLY INDUCED FLOW BETWEEN TWO MICRO-ECCENTRIC CYLINDERS

2017 ◽  
Author(s):  
Xiao-Jun Gu ◽  
David R. Emerson
Keyword(s):  
Thermally Induced ◽  
Eccentric Cylinders ◽  
Induced Flow

Thermally Induced Flow in a Rotating Annulus Filled With a Compressible Fluid

1988 ◽  
Vol 110 (2) ◽  
pp. 134-139 ◽  
Author(s):  
M. A. Ortega ◽  
J. T. Sielawa
Keyword(s):  
Flow Field ◽  
Inner Core ◽  
Temperature Fields ◽  
Bottom Plate ◽  
Rossby Number ◽  
Thermally Induced ◽  
Coaxial Cylinders ◽  
Induced Flow ◽  
Velocity And Temperature Fields ◽  
Induced Velocity

The thermally induced flow field, in a rapidly rotating container consisting of a pair of coaxial cylinders bounded on the top and bottom by horizontal end plates, is considered. The top plate is heated and the bottom plate is cooled, both by small amounts, so that the thermal Rossby number is small, and the cylinders are supposed to be conductive. The induced velocity and temperature fields are determined by subdivision of the flow field; the equation for the central part, the inner core, is solved numerically as well as analytically.

Testing Long-Term Predictions from Hydro-Geochemical Models

1993 ◽  
Vol 333 ◽  
Author(s):  
William E. Glassley ◽  
Carol J. Bruton ◽  
William L. Bourcier
Keyword(s):  
Yucca Mountain ◽  
Taupo Volcanic Zone ◽  
Ambient Conditions ◽  
Volcanic Zone ◽  
Site Specific ◽  
Thermally Induced ◽  
Induced Flow ◽  
Geochemical Models ◽  
Kinetics And Thermodynamic

ABSTRACTThermally induced flow of liquid water and water vapor at the potential repository site at Yucca Mountain, Nevada, will extend hundreds of meters away from the repository edge. The resultant transfer of heat and mass will sufficiently perturb the ambient conditions such that a variety of mineralogical and chemical reactions will occur that may modify hydrological properties. The consequences of this “coupling” of geochemical and hydrological processes will vary through time, and will occur to different degrees in four regimes (T < Tboiling; T = Tboiling; T > T boiling; cooling) that will develop within the repository block. The dominant processes in the regimes differ, and reflect the local balance between: 1) kinetics and equilibrium; 2) dissolution and precipitation; 3) evaporation and boiling; and 4) fluid flow in matrix and fractures. Simulations were conducted of the evolution of these regimes, using laboratory derived kinetics and thermodynamic data, and site specific mineralogical and hydrological properties. These simulations identify regions where chemical and mineralogical equilibrium is likely to be achieved, and where net changes in hydrological properties will be concentrated. Tests of the results of these simulations have been initiated using field data from the Taupo Volcanic Zone, New Zealand. A preliminary series of calculations suggest that relative changes in porosity of as much as ± 20% to 30% may be possible for rocks with an initial porosity of 10%.

An Experimental Investigation of the Thermally Induced Flow Oscillations in Two-Phase Systems

1976 ◽  
Vol 98 (4) ◽  
pp. 616-622 ◽  
Author(s):  
P. Saha ◽  
M. Ishii ◽  
N. Zuber
Keyword(s):  
Experimental Data ◽  
Phase Flow ◽  
Subcooled Boiling ◽  
Two Phase ◽  
Thermally Induced ◽  
System Pressure ◽  
Flow Oscillations ◽  
Induced Flow ◽  
Phase Systems ◽  
Nonequilibrium Theory

An experimental study on the onset of thermally induced two-phase flow oscillations has been carried out in a uniformly heated boiling channel using Freon-113 as the operating fluid. The effects of inlet subcooling, system pressure, inlet and exit restrictions, and inlet velocity have been studied. The experimental data have been compared with the equilibrium as well as the nonequilibrium theory including the effect of subcooled boiling. It has been found that the effect of thermal nonequilibrium should be included in a theoretical model for accurate prediction of the onset and the frequency of thermally induced flow oscillations. A simplified stability criterion has also been presented and compared with the experimental data.

An Experimental Study of Thermally-Induced Flow Oscillations in Supercritical Helium

1979 ◽  
Vol 101 (1) ◽  
pp. 9-14 ◽  
Author(s):  
D. E. Daney ◽  
P. R. Ludtke ◽  
M. C. Jones
Keyword(s):  
Stability Boundary ◽  
Density Wave ◽  
Oscillation Period ◽  
Expansion Ratio ◽  
Thermally Induced ◽  
Heated Channel ◽  
Flow Oscillations ◽  
Induced Flow ◽  
Point Data ◽  
Inception Point

The density wave stability boundary has been experimentally determined for super critical helium flowing in a long (L = 185 m), heated channel of high aspect ratio (L/d = 46 (10)4). A pressure drop ratio and the fluid expansion ratio correlate the oscillation inception point data. The growth of enthalpy (temperature) perturbations in a heated channel has been experimentally verified. During the density wave oscillation, the channel exit temperature and inlet mass flow were observed to be in phase, and the oscillation period was close to twice the fluid transit time. All three observations agree with a simple incompressible flow model. Oscillation amplitudes as great as 11 K and 100 percent of inlet flow were observed.

scholarly journals Study of Flow Characteristics of Gas Mixtures in a Rectangular Knudsen Pump

Micromachines ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 79 ◽  
Author(s):  
Zhijun Zhang ◽  
Xiaowei Wang ◽  
Lili Zhao ◽  
Shiwei Zhang ◽  
Fan Zhao
Keyword(s):  
Flow Characteristics ◽  
Direct Simulation Monte Carlo ◽  
Gas Mixtures ◽  
Thermal Creep ◽  
Temperature Fields ◽  
Thermally Induced ◽  
Creep Effect ◽  
Molecular Masses ◽  
Induced Flow ◽  
Knudsen Pump

A Knudsen pump operates under the thermal transpiration effect or the thermal edge effect on the micro-scale. Due to the uneven temperature distribution of the walls in the channel axis direction or the constant temperature of the tips on the walls, directional thermally-induced flow is generated. In this paper the Direct Simulation Monte Carlo (DSMC) method is applied for N2–O2 gas mixtures in the ratios of 4:1, 1:1, and 1:4 with different Knudsen numbers in a classic rectangular Knudsen pump to study the flow characteristics of the gas mixtures in the pump. The results show that the changing in the gas physical properties does not affect the distribution of the velocity field, temperature fields, or other fields in the Knudsen pump. The thermal creep effect is related to the molecular mass of the gas. Even in N2 and O2 gas mixtures with similar molecular masses, N2 can be also found to have a stronger thermal creep effect. Moreover, the lighter molecular weight gas (N2) can effectively promote the motion of the heavier gas (O2).

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