Conjugate natural convection combined with surface thermal radiation in an air filled cavity with internal heat source

Experimental and numerical investigations on optimal distribution of heat source array under natural and forced convection in a horizontal channel

Experiments have been conducted from five protruding rectangular discrete heat sources (aluminum) of non-identical sizes arranged at different positions on a substrate board (Bakelite), under natural convection, to determine their optimal configuration. A substrate board is designed for conducting experiments on multiple configurations of heat sources using the same board. A heuristic non-dimensional geometric parameter, λ, is defined for the purpose of identifying the optimal configuration for which the maximum temperature excess among the five heat sources of a configuration is the minimum, among all possible configurations. The maximum temperature excess is found to decrease with λ, so the configuration with highest λ is deemed to be the optimal one. The effect of surface radiation on the heat transfer rate from the heat sources is studied by painting their surfaces with black paint of high emissivity, which reduces their temperature by as much as 15%. An empirical correlation is developed for the non-...

Optimal Distribution of Discrete Heat Sources Under Natural Convection Using ANN–GA Based Technique

A novel concept of discrete heat source array with dummy components cooled by forced convection in a vertical channel

Aerodynamics analysis of superheated steam flow through multi-stage perforated plates

Experiments have been conducted for natural convection heat transfer from protruding discrete heat sources, mounted at different positions on a substrate, to determine the optimal configuration, and to study the effect of surface radiation on them, which reduces their temperature upto 12 %. The optimal configuration has been determined by a non-dimensional geometric distance parameter (λ). An empirical correlation has been proposed between the non-dimensional steady state temperature (θ) and λ, by taking into account the effect of surface radiation heat transfer.

Effect of surface radiation heat transfer on the optimal distribution of discrete heat sources under natural convection

This paper reports the results of an experimental investigation of fluid flow and heat transfer carried out with square jets issuing from perforated nozzles. This is accomplished by an impinging square jet on a uniformly heated plate of finite thickness (5 mm). The medium under consideration is air. Three different nozzle configurations are used in the study namely a single nozzle and perforated nozzles with four and nine holes, which are accommodated in the same available jet area 4.6 mm × 4.6 mm. This arrangement is akin to introducing a wire mesh at the nozzle exit plane. The effects of dimensionless jet-to-plate distance (2–9) and the mass flow rate of the jet fluid on the heat transfer rate are studied. Jet centerline mean velocity and turbulence intensity measurements are made with a hot-wire anemometer. The pressure drop across the orifice nozzle plate is measured and corresponding pumping power values are calculated. A comparison of the heat transfer performance and pumping power penalty of the three nozzle configurations is done.

Experimental investigation on heat transfer from square jets issuing from perforated nozzles

Experimental investigation on the effect of wire mesh at the nozzle exit on heat transfer from impinging square jets

Nanoclay weight percent, glass fiber volume percent and angle of orientation of fibers were selected as parameters to study their effect on tensile and flexural characteristics of epoxy-glass-clay nanocomposites (EGCNs). Response surface method (RSM) was utilized to analyze and fit a regression model for the tensile and flexural strength. The optimum values of ultimate tensile strength (UTS) and flexural strength (σf) were 273.47 and 210.14 MPa, respectively, which were predicted using regression models at 2.5% (by wt) of nanoclay, 31.5% (by vol) of glass fiber and 0°/90° of fibers orientation. The predicted results were confirmed by performing experiments at the optimum conditions which were obtained as 262.37 and 214.76 MPa. The optimized result showed that UTS and σf were improved up to 30.8% and 36.3% compared to the composite containing 0% (by wt) of nanoclay, 31.5% (by vol) of glass fiber and 0°/90° of fibers orientation. The optimum values of tensile and flexural modulus were obtained as 25.99 and 11.81 GPa, respectively, which were 12.2% and 10.7% higher compared to those values of EGCN containing 0% (by wt) of nanoclay, 31.5% (by vol) of glass fiber and 0°/90° of fibers orientation. XRD test conducted to check the intercalation/exfoliation of the clay in the composite. The fracture surfaces of the EGCNs investigated by scanning electron microscopy (SEM) revealed that the failure occurred by crack propagation in the matrix followed by fiber breakage with little fiber-matrix debonding, whereas in case of EGCN with 0% (by wt) C15A fiber-matrix debonding followed by fiber breakage was observed.

Tensile and flexural characteristics of an epoxy-glass composite reinforced with Cloisite 15A nanoclay

The influence of flow blockage elements at the orifice exit on the hydrodynamic and thermal performances of impinging square jets - an experimental investigation

Pullarao Muvvala

Papers

Effect of surface radiation heat transfer on the optimal distribution of discrete heat sources under natural convection

Experimental investigation on heat transfer from square jets issuing from perforated nozzles

Experimental investigation on the effect of wire mesh at the nozzle exit on heat transfer from impinging square jets

Tensile and flexural characteristics of an epoxy-glass composite reinforced with Cloisite 15A nanoclay

The influence of flow blockage elements at the orifice exit on the hydrodynamic and thermal performances of impinging square jets - an experimental investigation