this paper presents an exact analytical solution for two-dimensional conductive heat transfer in spherical composite pressure vessels .the vessels are in spherical shape and fibers are winded in circumferential direction. the analytical solution is obtained under the general boundary conditions which consist of convection, conduction and radiation inside/outside of vessel. the heat transfer equ...

Computational models are developed to predict the natural convection heat transfer and buoyancy for a Montgolfiere under conditions relevant to the Titan atmosphere. Idealized single and double-walled balloon geometries are simulated using algorithms suitable for both laminar and (averaged) turbulent convection. Steady-state performance results are compared to existing heat transfer coefficient...

Passive heat transfer from enclosures with rectangular fins is studied both experimentally and theoretically. Several sample enclosures with various lengths are prepared and tested. To calibrate the thermal measurements and the analyses, enclosures without fins (“bare” enclosures) are also prepared and tested. Surface temperature distribution is determined for various enclosure lengths and heat...

A lattice Boltzmann model is developed by coupling the density (D2Q9) and the temperature distribution functions with 9-speed to simulate the convection heat transfer utilizing Al2O3-water nanofluids in a square cavity. This model is validated by comparing numerical simulation and experimental results over a wide range of Rayleigh numbers. Numerical results show a satisfactory agreement between...

The effect of time-periodic oscillations of the RayleighBénard system on the heat transport in dielectric liquids is investigated by weakly nonlinear analysis. We focus on stationary convection using the slow time scale and arrive at the real GinzburgLandau equation. Classical fourth order Runge-kutta method is used to solve the Ginzburg-Landau equation which gives the amplitude of convection a...

The interplay of buoyancy and thermo-magnetic convection mechanisms are investigated in a horizontal ferrofluid layer heated from one wide side and cooled from another in the presence of external uniform transversal magnetic field. The influence of gravitational settling of magnetic particles and their aggregates on heat transfer and convection instability is also considered. The ferro-colloids...

Restratification after deep convection, a key factor in determining the temporal variability of dense water formation in the Labrador Sea, is governed by lateral buoyancy fluxes. The role of three different eddy types in this process is assessed using an idealized model to simulate the restratification season. For a realistic shape of the convection area, it is shown that in the model warm core...

conv hAs (Ts T ) where As is the heat transfer surface area and h is the convection heat transfer coefficient. When the temperatures Ts and T are fixed by design considerations, as is often the case, there are two ways to increase the rate of heat transfer: to increase the convection heat transfer coefficient h or to increase the surface area As. Increasing h may require the installation of a p...

In this paper, natural convection heat transfer of CuO-water Nanofluid within a wavy-walled cavity and subjected to a uniform magnetic field is examined by adopting the lattice Boltzmann model. The left wavy wall is heated sinusoidal, while the right flat wall is maintained at the constant temperature of Tc. The top and the bottom horizontal walls are smooth and insulated against heat and mass....

This study examines experimentally the heat loss from a model solar cavity receiver. For this purpose, laboratory-scale cylindrical cavity models with geometric aspect ratios (cavity length to diameter) of 1 and 2, and aperture opening ratios (aperture diameter to cavity diameter) of 0.5 and 1, were built. Each cavity was subjected to constant boundary heat input via heating cables, and was ope...