Aspects of modeling the effect of temperature stratification in the vortex tube channel

2010 ◽  
Vol 7 ◽  
pp. 163-171
Author(s):  
D.F. Marin ◽  
C.I. Mikhaylenko ◽  
L.H. Khaziev
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Energy Distribution ◽  
Large Particle ◽  
Vortex Tube ◽  
Particle Method ◽  
Effect Of Temperature ◽  
Hot Air ◽  
Cylindrical Coordinate ◽  
Tube Channel

A direct numerical simulation of the Ranque-Hilsch effect in a counterflow vortex tube with a diameter of the hot air diaphragm coinciding with the diameter of the tube was performed. We used DNS-modeling on the basis of the large-particle method in a cylindrical coordinate system, which allows us to take into account the scale of large turbulent vortices. An analysis of the energy distribution in the system under consideration gave a picture of the temperature distribution in the volume of the vortex tube.

The influence of the vortex tube channel length on the separation of air by its temperature

2019 ◽  
Vol 14 (1) ◽  
pp. 36-43
Author(s):  
B.R. Adiullin ◽  
C.I. Mikhaylenko
Keyword(s):  
Atmospheric Pressure ◽  
Constant Pressure ◽  
Vortex Tube ◽  
Channel Length ◽  
Ideal Gas ◽  
Hot Air ◽  
Conservation Of Momentum ◽  
Mass Flow Rates ◽  
Vortex Tubes ◽  
Tube Channel

Based on the prepared counterflow vortex tube model with four inlets, the effect of the length of the vortex tube channel on the generation of cold and hot air is investigated. In the simulation were used standard equations of gas dynamics, which include the equations of continuity, conservation of momentum, total energy, and the state of an ideal gas. To consider turbulent effects was chosen a -\varepsilon$ turbulence model. Computational experiments were carried out in the OpenFOAM software using the sonicFoam solver. The prepared grid allowed modeling vortex tubes with the main channel length varying from 20 to 70 cm. All calculations were carried out under the same boundary conditions with constant pressure at the inlets and atmospheric pressure at the hot and cold outlets. The constructed model adequately reproduces the two-vortex structure of the air flow in the vortex tube. To obtain and process the results were used OpenFOAM utilities and a script implementing the algorithm for averaging the values at the tube outlets written in Python. The results were obtained on the temperatures and mass flow rates of air in cold and hot outlets of the vortex tube depending on the length of the device. According to the analysis of the obtained data, it was shown that increasing the length of the channel of the vortex tube significantly increases the production of cold air with a certain increase in its temperature. An increase in the temperature of the produced hot air with an increase in the length of the vortex tube was also noted.

The Effect of Using Ramps with Trench Cylindrical Holes on Film Cooling Effectiveness

2015 ◽  
Vol 3 (2) ◽  
pp. 15-27
Author(s):  
Ahmed A. Imram ◽  
Humam K. Jalghef ◽  
Falah F. Hatem
Keyword(s):  
Numerical Simulation ◽  
Film Cooling ◽  
Air Injection ◽  
Baseline Model ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Blowing Ratio ◽  
Hot Air ◽  
Test Study ◽  
Cylindrical Holes

     The effect of introducing ramp with a cylindrical slot hole on the film cooling effectiveness has been investigated experimentally and numerically. The film cooling effectiveness measurements are obtained experimentally. A test study was performed at a single mainstream with Reynolds number 76600 at three different coolant to mainstream blowing ratios 1.5, 2, and 3. Numerical simulation is introduced to primarily estimate the best ramp configurations and to predict the behavior of the transport phenomena in the region linked closely to the interaction between the coolant air injection and the hot air mainstram flow. The results showed that using ramps with trench cylindrical holes would enhanced the overall film cooling effectiveness by 83.33% compared with baseline model at blowing ratio of 1.5, also  the best overall flim cooling effectevness was obtained at blowing ratio of 2 while it is reduced at blowing ratio of 3.

Experimental and Numerical Evaluation of Small-Scale Cryosurgery Using Ultrafine Cryoprobe

2013 ◽  
Vol 4 (4) ◽  
Author(s):  
Junnosuke Okajima ◽  
Atsuki Komiya ◽  
Shigenao Maruyama
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Transfer Coefficient ◽  
Temperature Distribution ◽  
Surface Temperature ◽  
Numerical Evaluation ◽  
Small Scale ◽  
Outer Diameter ◽  
Cooling Performance ◽  
The Heat Transfer Coefficient

The objective of this work is to experimentally and numerically evaluate small-scale cryosurgery using an ultrafine cryoprobe. The outer diameter (OD) of the cryoprobe was 550 μm. The cooling performance of the cryoprobe was tested with a freezing experiment using hydrogel at 37 °C. As a result of 1 min of cooling, the surface temperature of the cryoprobe reached −35 °C and the radius of the frozen region was 2 mm. To evaluate the temperature distribution, a numerical simulation was conducted. The temperature distribution in the frozen region and the heat transfer coefficient was discussed.

scholarly journals MATHEMATICAL MODELLING AND COMPUTER SIMULATION OF TEMPERATURE DISTRIBUTION IN INHOMOGENEOUS COMPOSITE SYSTEMS WITH IMPERFECT INTERFACE

2014 ◽  
Vol 6 (2) ◽  
pp. 77-85
Author(s):  
Pratibha Joshi ◽  
Manoj Kumar
Keyword(s):  
Numerical Simulation ◽  
Heat Flux ◽  
Temperature Distribution ◽  
Imperfect Interface ◽  
Immersed Interface Method ◽  
Immersed Interface ◽  
Composite Systems ◽  
Steady State Temperature ◽  
Perfect Interface ◽  
Inhomogeneous Composite

Many studies have been done previously on temperature distribution in inhomogeneous composite systems with perfect interface, having no discontinuities along it. In this paper we have determined steady state temperature distribution in two inhomogeneous composite systems with imperfect interface, having discontinuities in temperature and heat flux using decomposed immersed interface method and performed the numerical simulation on MATLAB.

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