We shall describe the diffusion of heat energy through a long thin rod G with uniform cross section S. As before, we identify G with the open interval (a, b), and we assume the rod is perfectly insulated along its length. Let u(x, t) denote the temperature within the rod at a point x ∈ G and at time t > 0. Our previous experience shows that the heat flux q(x, t) at the point x, i.e., the flow r...

in this numerical study the the heat transfer and laminar nanofluid flow in the three-dimensional microchannels with triangular cross-section is simulated. for increase the heat transfer from the walls of the channel, semiattached & offset mid- truncated rib,s placed in the canal, and the tooth geometry and the impact is studied. in this study, the water is base fluid, and the influence of the ...

We present a dynamic van der Waals theory. It is useful to study phase separation when the temperature varies in space. We show that, if heat flow is applied to liquid suspending a gas droplet at zero gravity, a convective flow occurs such that the temperature gradient within the droplet nearly vanishes. As the heat flux is increased, the droplet becomes attached to the heated wall that is wett...

1. A calorimeter for the continuous measurement of heat production and heat loss in the human subject, for at least 24 h, is described. The calorimeter operated on the heat-sink principle for direct calorimetry and an open-circuit system for indirect calorimetry. 2. Sensible heat loss was measured using a water-cooled heat exchanger, and the temperature of water entering the heat exchanger was ...

In this work a numerical investigation of transient temperature profile of laser beam welding process is carried out. A 3-D finite element modelling isdevelopedconsidering combined double-ellipsoidalheat source model for both spot and moving heat source. The temperature dependent thermo-physical material property of Ti-6Al-4V alloy isincorporated. The effect of latent heat of fusion and convect...

The usual way to model heat conduction is to solve a partial differential equation (PDE) with boundary conditions (BCs), i.e., a boundary value problem (BVP). For the case of steady-state heat conduction in a homogeneous isotropic solid with thermal conductivity independent of temperature and with no heat source inside the solid, temperature T (x, y, z) in the solid verifies Laplace equation [5] :

A perturbation technique is proposed for solution of the generalized equations governing the thermal behaviour of thin metal ®lms described by a hyperbolic two-step model. The generalized equations of this model contains diffusion terms in both the electron and lattice energy equations and assumes that incident laser radiation is absorbed by both the electron gas and solid lattice to account fo...

In the current study, reduction of nitrogen oxide from exhaust gas in the presence of NH3 as reductant on selective catalytic reductant (SCR) impregnated catalytic converter was simulated using Comsol© software. Mass transfer (one-dimensional) and heat transfer (three-dimensional) governing equations were taken into account to model the unsteady state behavior of the catalytic converter. Modeli...

A novel, patented topping power cycle is described that takes its energy from a very high-temperature heat source and in which the temperature of the heat sink is still high enough to operate another, conventional power cycle. The top temperature heat source is used to evaporate a low saturation pressure liquid, which serves as the driving fluid for compressing the secondary fluid in an ejector...

Battery impedance is essential to the management of lithium-ion batteries for electric vehicles (EVs), and impedance characterization can help to monitor and predict the battery states. Many studies have been undertaken to investigate impedance characterization and the factors that influence impedance. However, few studies regarding the influence of the internal temperature gradient, which is c...