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Proceedings ArticleDOI

Experimental investigation of natural convection in a rectangular cavity with two protruded half cylinders using a Mach-Zehnder interferometer

TL;DR: In this paper, an experimental investigation is performed in a rectangular cavity of dimension 46 mm x 23 mm with protruded copper half cylinders of diameter 15.8 mm (5/8 inch) each.
Abstract: Natural convection studies in an enclosure are very relevant since it spans a wide area of applications such as heat exchangers, chemical reactors, cooling of electronic equipment, etc. In the present study, an experimental investigation is performed in a rectangular cavity of dimension 46 mm x 23 mm with protruded copper half cylinders of diameter 15.8 mm (5/8 inch) each. Interferometry has always been a good technique for accurate measurements of temperature gradients. Mach-Zehnder interferometer is employed for visualising the isotherms and for quantitatively inferring the temperature gradient. The protruded half cylinders are maintained at constant temperature, ranging from 60°C to 120°C using an electric cartridge heater and associated temperature controller setup. A He-Ne laser with 24mm collimated beam size is used for experimental purposes. Temperature gradient variation along the radial direction is plotted against the circumferential angle of the cylinder and isotherm merging angle is determined for varying time step and varying cylinder surface temperature.
Citations
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Journal ArticleDOI
TL;DR: In this article, an optical shadow method was used to evaluate the falling film thickness around the circumference of a horizontal tube, where a Mach-Zehnder Interferometer was employed to visualize the isotherm formation.

6 citations

Journal ArticleDOI
TL;DR: In this article , the authors investigated the potential use of heat and mass transfer enhanced surfaces for horizontal tube falling film evaporator to scale up its effectiveness, which is a class of heat exchanger that is widely studied.

2 citations

References
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BookDOI
01 Jan 1983
TL;DR: In this article, the physical laws of fluid mechanics and their application to measurement techniques are discussed, as well as the application of these laws to flow visualization and flow visualization by direct injection.
Abstract: Contributors Preface Preface to the First Edition 1.What Do We Measure and Why? 2.Physical Laws of Fluid Mechanics and Their Application to Measurement Techniques 3.Thermal Anemometers 4.Laser Velocimetry 5.Volume Flow Measurements 6.Flow Visualization by Direct Injection 7.Optical Systems for Flow Measurement:Shadowgraph Schlieren, and Interferometric Techniques 8.Fluid Mechanics Measurements in Non-Newtonian 9.Measurement of Wall Shear Stress 10.Acquiring and Processing Turbulent Flow Data Index

628 citations

Journal ArticleDOI
TL;DR: In this paper, a two-dimensional solution for unsteady natural convection is obtained, using the immersed boundary method (IBM) to model an inner circular cylinder based on the finite volume method for different Rayleigh numbers varying over the range of 103-106.

350 citations

Journal ArticleDOI
TL;DR: In this paper, a numerical and experimental analysis is performed for natural convection heat transfer from a horizontal cylinder enclosed in a rectangular cavity, where the temperature distribution in the air and the heat transfer coefficients are measured by a holographic interferometer and compared with numerical predictions obtained by a finite-element procedure based on the streamfunction-vorticity formulation of the momentum equations.

171 citations

Journal ArticleDOI
TL;DR: In this paper, a general formulation to treat mixed boundary conditions using the spline approximation has been presented, where numerical solutions have been obtained by solving the Navier-Stokes and energy equations.
Abstract: The present work is devoted to the numerical study of laminar natural convection flow from a heated horizontal cylinder under diverse surface boundary conditions using the spline fractional step method. A general formulation to treat mixed boundary conditions using the spline approximation has been presented. Numerical solutions have been obtained by solving the Navier-Stokes and energy equations. The results for the isothermal boundary condition as well as for the uniform heat flux are in good agreement with published experimental data and with other solutions presently available in the literature. Some new computations at very high Rayleigh numbers indicate the existence of attached separation vortices in the downstream plume region, the appearance of these vortices being dependent on the values of the Biot number. All results were computed on a personal computer using unequally spaced grids that provided good results with a minimum number of computational points. The numerical scheme presented here app...

103 citations

Journal ArticleDOI
TL;DR: In this article, a numerical investigation of laminar convective flows in a differentially heated, square enclosure with a heat-conducting cylinder at its center is carried out, where the flow and the temperature are computed using respectively the lattice Boltzmann equation and finite-difference with suitable coupling to take natural convection into account.

99 citations


"Experimental investigation of natur..." refers methods in this paper

  • ...From further deductions in the above formula, with first order relation between density and temperature and if the beam transmit through a region of varying density, the path difference induced is measured using the equation:   1 2 ( ) dn PL T T L dT      (2) One fringe shift is generated by path length difference of  , which is accounted to a temperature difference of T  , T dn L dT           (3)...

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