Showing papers by "Annamalai Mani published in 2017"
TL;DR: In this paper, the effect of heat input, cooling water flow rate, cooling temperature and fill ratio on the thermal response of a flat heat pipe with and without wick columns was investigated.
27 citations
TL;DR: In this paper, the performance and flow structure in a three-dimensional rectangular ejector have been numerically investigated by using air as the working fluid, and the authors aim to optimize the convergent-divergent (C-D) nozzle position for each operating condition and to bring out the influence of reflected shock waves and boundary layer in the constant area mixing chamber.
16 citations
TL;DR: In this article, a two-dimensional computational fluid dynamics study of water falling film evaporation on a thermal spray metal coated vertical corrugated conduits was performed by using a finite volume method-based commercial software, using k-ω equations with shear stress transport.
Abstract: In falling film evaporation process, the heat is transferred from the condensing fluid side to the liquid flowing on evaporating side. Tube geometry and tube size have an important role on the performance of the falling film evaporators. The current article presents a two-dimensional computational fluid dynamics study of water falling film evaporation on a thermal spray metal coated vertical corrugated conduits. Two-phase flow simulation is carried out by using a finite volume method-based commercial software, using k-ω equations with shear stress transport. Sinusoidal corrugations with different porosity have been selected for this study. Heat and mass transfer during falling film evaporation are included through user defined functions. Effect of Reynolds number, wall superheat, and surface roughness on heat transfer coefficient is presented. Numerical results are compared with the results of horizontal circular tube, as well as corrugated plate conduits falling film evaporation from literature. An enhan...
7 citations
TL;DR: In this article, a transparent organic nonlinear optical single crystal was grown by slow evaporation method and the crystal structure was confirmed by single and powder X-ray diffraction studies.
Abstract: High quality and transparent organic nonlinear optical single crystal - β alanine β alaninium picrate (βAβAP) of 12 × 8 × 3 mm in dimensions was grown by slow evaporation method. The crystal structure was confirmed by single and powder X-ray diffraction studies. The perfection of the grown crystal is justified by High resolution XRD measurement. The strain of the crystal in grain boundary was calculated from the powder XRD pattern values. The Photo luminescence’s (PL) study is also investigated to predict the optical perfection of the crystal. Optical constants like, absorption coefficient, extinction coefficient, reflection, refractive index and optical band gap are calculated using UV–Vis absorption spectrum. Optical limiting method is involving to find the linear optical absorption. The birefringence of the crystal was measured in the visible region and it was found that birefringence is dependent of wavelength. The crystal was subjected to Z-scan measurement to prove the third order non linear optical property of the crystal. The thermal stability of the crystal against the high intense laser power is measured using laser damage threshold study.
6 citations
3 citations
23 Aug 2017
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.
2 citations