Partially Heated Research Articles

Plane Thermal Stresses in a Functionally Graded Plate Subjected to a Partial Heating

This paper presents plane thermal stresses in a functionally graded plate (FGP) subjected to a partial heating. The heat conductivity, Young's modulus and the coefficient of the linear thermal expansion are expressed by exponential functions of the position. The analytical solution for the FGP with two-dimensional temperature distribution is obtained by use of the stress function method. General solution of the governing equation of the stress function is derived in the functionally graded materials (FGMs). The numerical calculations are carried out for ZrO2/Ti-6 Al-4 V and ZrO2{/} stainless (SUS304) functionally graded plates, when the ceramic surface is partially heated. The numerical results are shown in figures for two cases. Even though the FGM, suitable selection of the compositional materials does not produce thermal stresses in the FGP.

Entropy generation in a square enclosure with partial heating from a vertical lateral wall

The entropy generation during the transient laminar natural convection in a square enclosure that is partially heated from a vertical lateral wall is numerically investigated. The active sites referring to the main irreversibility locations are determined. The Boussinesq approximation is used in the natural convection modelling. The effects of Prandtl (Pr) and Rayleigh (Ra) number combinations on the entropy generation are investigated. The study is restricted to the fluids of Prandtl number from 0.01 to 1.0, and Rayleigh numbers in the range of 102–108. It is found that the upper corner of the heated part of the side wall is the active site where the entropy generation initiates due to irreversibilities representing the energy loss.

Heat and mass transfer with phase change in aporous structure partially heated: continuum model andpore network simulations

The heat and mass transfer within a porous structure with partial heating andvaporization on the upper surface is studied numerically. Two models are presented: a continuum (Darcy) model and a pore network model. Both approaches show that the liquid-vapor frontenters inside the porous structure. When the structure is characterized by a single pore size, the continuum model and the pore network model lead to the same stationary solution and the liquid–vapor front is smooth. When there exists a pore size distribution, pore network simulations show that the front resembles fractal fronts typical of invasion percolation. Implications of the results to capillary pumped loops (CPL) are discussed. In particular, the results indicate that capillary fingering may limit the operating range of CPL.

Natural convection in rectangular enclosures with partial heating and cooling

The flow and heat transfer in partially heated and partially cooled cavities were numerically analyzed. Using the control volume approach, a computer program based on SIMPLE algorithm was developed. A square enclosure with variable size heater and cooler on the vertical walls was considered. Computations were carried out to investigate the effects of heater and cooler size on the heat transfer rate. It was observed that for a given cooler size, the mean Nusselt number decreases with increasing heater size. On the other hand, for a given heater size, the mean Nusselt number increases with increasing cooler size. For all Rayleigh numbers considered, the same behavior was observed.