Coefficient of heat conduction

A I - coefficients of heat conduction for both halves of a cell,... 

One way of covering this for the heat conduction equation is to construct a homogeneous conservative scheme by means of the integro-interpo-lation method. To make our exposition more transparent, we may assume that the coefficient of heat conductivity k = k(x) is independent of t. The general case k = k(x,t) will appear on this basis in Section 8 without any difficulties. 

The equation with a discontinuous coefficient of heat conductivity. In... 

Nonlinearity of the coefficient of heat conductivity results in the new physi- cal effects, the main of which is a final velocity of heat conducting. In what S... 

A case in point is a nonlinear dependence of the coefficient of heat conductivity upon the temperature. From the formula for D it is easily seen that we formally have D = oo for the linear heat conductivity when (7 = 0 meaning that the velocity of heat conducting turns out to be infinite. 

The Stephan problem (problem of the phase transition). Subsequent considerations include two phases with the coefficients of heat conductivity fej(u), k. u) and of heat capacity Cj(r<), c iu), in either of which it is... 

From here it seems clear that the admissible step in the explicit scheme is yet to be refined along with increasing the maximum value of the coefficient of heat conductivity. As a matter of fact, the last requirement is unreal for the problems with fastly and widely varying coefficients. Just for this reason explicit schemes are of little use not only for multidimensional problems, but also for one-dimensional ones (p = 1). On the other hand, the explicit schemes ofl er real advantages that the value y = on every new layer + t is found by the explicit formulas (3) with a finite... 

The process of heat propagation in a flat homogeneous medium G with constant thermal-physical properties (p is density, c is specific heat capacity, and K is the coefficient of heat conductivity p,C,K = const > 0) is described by... 

C = coefficient of heat conductivity measured in heat units per unit time per unit of packing volume per deg temperature difference usual units are cal per sec per deg C per cc m = a constant for limestone packings, m = 0.0073 for iron ore, 0.0105 anthracite and other coals, 0.0050 blast-furnace charge, 0.0072. The values are in metric units. q = volume of gas flow per unit-time per square unit of cross-sectional packing area, expressed as liters per sec per sq cm T = temperature, deg abs, C = fractional voids (dimensionless) d = diameter of particles, cm... 

Limestone having an average diameter of 3 cm is packed in a 100-cm cylindrical column. The voids are calculated to be 34.5 percent. Air having a temperature of 320 deg C is made to flow through the column at a rate of 500 liters per sec. Determine the coefficient of heat conductivity. 

The coefficient k is called the heat conductivity factor. In parallel with this, the factor of thermal diffusivity is frequently used in practice (sometimes also called the coefficient of heat conductivity)... 

The dimensions of a are the same as those of the diffusion coefficient and of the kinematic viscosity, therefore the process of heat transport due to conduction can be treated as the diffusion of heat with the diffusion coefficient a, bearing in mind that the transport mechanisms of diffusion and heat conductivities are identical. The coefficient of heat conductivity of gases increases with temperature. For the majority of liquids the value of k decreases with increasing T. Polar liquids, such as water, are an exception. For these, the dependence k(T) shows a maximum value. As well as the coefficient of viscosity, the coefficient of heat conductivity also shows a weak pressure-dependence. 

Usually, instead of phenomenological coeflRcients, other coefficients are introduced the coefficient of heat conductivity 2 = the Dufour coefficient... 

The coefficient of heat conduction is considered as an average of the heat conduction through the skeleton A and the moisture A0 that is. 

COEFFICIENTS OF HEAT CONDUCTIVITY OF LIQUIDS AND THEIR MIXTURES. 

---