Eddy resolving simulation of mixed convection in a rotating annular cavity with one heated disk and axial throughflow: the effect of the surface macro-relief

We present the results of hybrid RANS/LES computations of non-isothermal buoyant flow in a rapidly revolving enclosure with paraxial transit stream of the cooling air. Foil heat flux meters mounted on the disk surface in the base experiment are mimicked by means of the grid resolved macro-relief. The results obtained using the relief and smooth disk models are collated with available measurements. According to the simulation, the addition of the relief has resulted in switching from two to three pairs of cyclonic/anti-cyclonic global circulations, and the overall heat transfer rate has increased by 20%. It has been found also that the sensor readings can be up to 25% higher than the heat flux averaged over the circumference at the same radius. Despite this distinct effect of the surface relief, the local heat transfer rate is still underestimated considerably as compared to measurements.

Von Karman rotating nanofluid flow with modified Fourier law and variable characteristics in liquid and gas scenarios

This investigation aims to explore the temperature-dependent variable characteristics of viscosity, and thermal conductivity with modified Fourier law in a nanofluid flow over a rotating disk. The uniqueness of the envisioned mathematical model is improved with the additional impacts of the chemical reaction, non-uniform source/sink, and convective boundaries. The salient feature of the existing problem is to discuss the whole scenario with liquid and gas thermo-physical characteristics. The graphical depiction is attained for arising pertinent parameter is attained by using Bvp4c a built-in MATLAB function. The visco-thermal conduct of the gases and liquids is examined by observing the mean flow and thermal distributions for the convectively heated disk. It is followed that liquid behaves more viscous with an increase in temperature in of the gas, but an opposing tendency can be seen for the liquid. The attained results are verified when compared with a published result.

Analysis of Carreau fluid flow by convectively heated disk with viscous dissipation effects

The primary motive of this study is to examine boundary layer flow of Carreau fluid over a convectively heated disk stretching with nonlinear velocity. The flow is assumed to be two dimensional. Moreover, viscous dissipation possessions are taken into description. The dominating nonlinear differential equations involving partial derivatives are changed into nonlinear differential equations involving ordinary derivatives by applying suitable transformations. Numerical outcomes for velocity and temperature are obtained from MATLAB’s built-in solver bvp4c and presented graphically and in tabular form.

Effect of Prandtl Number on the Heat Transfer From a Rotating Disk: An Experimental Study

Heat transfer coefficients were experimentally determined for a free rotating disk in still air and water. These were obtained with an electrically heated disk placed in a cylindrical pool. The accuracy of the employed experimental apparatus was assessed by heat transfer measurements in air. For this fluid, an excellent agreement with reliable literature data was found. Essentially new experimental data were obtained for water as fluid. Based upon the experimental data, the validity of theoretical correlations and the effect of the Prandtl number on the convective heat transfer from a rotating disk were discussed. It was found that in laminar water flow, the value of the correlation exponent for the Prandtl number is practically identical to 1/2 as theoretically predicted in 1948 by Dorfman. In turbulent flow, its value is better given by 1/3 as in case of the classical turbulent boundary layer theory.