Heat Transfer Quiz 2_ Villanueva

This theory states that at least three factors must be known to establish the value of the average film coefficient of steam and organic vapors: the terminal Reynold's number, the Prandtl number of the condensed phase, and a dimensionless group Nd.

The spectral distribution of a perfect emitter has a maximum and that the corresponding wavelength depends on temperature. The maximum spectral emissive power is displaced to longer wavelengths.

The triangular center to center distance of a bank of 8 in OD tubes in a furnace is 8 inches. Estimate the total view factor, F directly intercepted by the first two rows of tubes.

________ states that: The exchange areas between two pairs of surfaces are equal when there is one-to-one correspondence for all sets of symmetrically positioned pairs of differential elements in the two surface combinations.

A thick-walled copper spherical tank has an inside radius of 1cm and an outside radius of 1.8 cm. The inner and outer surface temperatures are held at 305C and 295C respectively. Assume k varies linearly with temperature, with k_o = 371.9 W/m-K and b = -9.25 E-5 (1/K). Determine the heat loss per unit length.

A 5-m hemispherical furnace is composed 2 materials with thermal conductivities of k1 = 0.5 W/m-K and k2 = 0.9 W/m-K, respectively. One half of the dome is composed of 0.5 m of material 1 and the other is composed of 0.5 m of material 2. The convective heat transfer coefficient is 6 W/m2-K and the radiative heat-transfer coefficient is 20 W/m2-K. Find the inner temperature of the furnace when the surface temperature of the furnace is 400C. The surrounding temperature of the air is at 30C.

Suppose a fictitious metal plate (thickness = 8cm) is to be heated from 43C to 100C. The heating medium is 102C. The heat capacity, density, thermal conductivity and heat transfer coefficient are estimated to be c = 3500 J/kg-C, ρ = 1000 kg/m3, k = 0.5 W/m-K, and h = 0.6 W/m2-K, respectively. Find the total time it takes for this process to be completed. Suppose the initial conditions are stable and consider unsteady-state heat conduction.