Space specific heat

It is assumed that heat transfer proceeds via convective mass transfer being disturbed by axial heat conduction in accordance with eq. (20), where y and A.g denote a space-specific heat and the heat conductivity, respectively ... 

Dp = equivalent tube diameter, ft dp = equivalent tube diameter, in. a, = flow area across the tube bundle, fF B = baffle spacing, in. c = specific heat of fluid, Btu/lb (°F) p. = viscosity at the caloric temperature, Ib/ft (hr) py, = viscosity at the tube wall temperature, Ib/ft (hr)... 

In an oil cooler 216 kg/h of hot oil enters a thin metal pipe of diameter 25 mm. An equal mass flow of cooling water passes through the annular space between the pipe and a larger concentric pipe with the oil and water moving in opposite directions. The oil enters at 420 K and is to be cooled to 320 K. If the water enters at 290 K, what length of pipe will be required Take coefficients of 1.6 kW/m2 K on the oil side and 3.6 kW/tn2 K on the water side and 2.0 kJ/kg K for the specific heat of the oil. 

A single-effect evaporator is used to concentrate 7 kg/s of a solution from 10 to 50 per cent of solids. Steam is available at 205 kN/m2 and evaporation takes place at 13.5 kN/m2. If the overall heat transfer coefficient is 3 kW/m2 K, calculate the heating surface required and the amount of steam used if the feed to the evaporator is at 294 K and the condensate leaves the heating space at 352.7 K. The specific heat capacity of a 10 per cent solution is 3.76 kJ/kgK, the specific heat capacity of a 50 per cent solution is 3.14 kJ/kgK. 

Distilled water is produced from sea water by evaporation in a single-effect evaporator working on the vapour compression system. The vapour produced is compressed by a mechanical compressor of 50 per cent efficiency, and then returned to the calandria of the evaporator. Extra steam, dry and saturated at 650 kN/m2, is bled into the steam space through a throttling valve. The distilled water is withdrawn as condensate from the steam space. 50 per cent of the sea water is evaporated in the plant. The energy supplied in addition to that necessary to compress the vapour may be assumed to appear as superheat in the vapour. Calculate the quantity of extra steam required in kg/s. The production rate of distillate is 0.125 kg/s, the pressure in the vapour space is 101.3 kN/m2, the temperature difference from steam to liquor is 8 deg K, the boiling-point rise of sea water is 1.1 deg K and the specific heat capacity of sea water is 4.18 kJ/kgK. 

A single-effect evaporator with a heating surface area of 10 m2 is used to concentrate a NaOH solution flowing at 0.38 kg/s from 10 per cent to 33.3 per cent. The feed enters at 338 K and its specific heat capacity is 3.2 kJ/kg K. The pressure in the vapour space is 13.5 kN/m2 and 0.3 kg/s of steam is used from a supply at 375 K. Calculate ... 

A fire occurs in a space station at 200 kW. The walls can be considered adiabatic and of negligible heat capacity. The initial and fuel temperatures are at 25 °C. Assume the station atmosphere has uniform properties with constant specific heats as given. Assume that the constant and equal specific heats of constant pressure and volume are 1.2 and 1.0 kJ/kg K respectively. Conduct your analysis for the control volume (CV) consisting of the station uniform atmosphere, excluding all solids and the fuel in its solid state. 

Production of distillate = 0.125 kg/s, pressure in vapour space = 101.3 kN/m2, temperature difference from steam to liquor = 8 deg K, boiling point rise of sea water =1.1 deg K, specific heat capacity of sea water = 4.18 kJ/kg deg K. The sea water enters the evaporator at 344 K from an external heater. 

From band structure calculations as well as from experimental results (photoemission, specific heat...), it is now clear that, at least for magnetic compounds near the critical spacing, 5 f electrons are in bands. This means that contrary to the pure metals, the Stoner criterion may be fulfilled before the band description breaks down. 

In the Eulerian view, a fluid is characterized by fields of intensive variables or properties r). For example, the internal energy (or temperature, for a constant specific heat) is assumed to be a continuous function of time and space, r)(t,x). Because rj is a continuous differentiable function, the following expansion is generally valid ... 

The relationship between the x-ray measurements of the lattice constants of 6-6 Nylon and 6-Nylon (polyamides) as a function of temperature and the calorimetric data has already been discussed. Slichter (1958b) made an x-ray-temperature study of 6—10 polyamide and demonstrated that the 010 spacing rose with temperature, that the 100 spacing fell somewhat and that the two became equal at about 190° C. However, these lattice changes were too small to produce a noticeable effect in the specific heat measurements. If anything, the specific heat decreased from 160 to 180° C the subsequent rise was due in part, at least, to the onset of melting. 

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