Obtain the Taylor-Prandtl modification of the Reynolds analogy between momentum and heat transfer and give the corresponding analogy for mass transfer. For a particular system a mass transfer coefficient of 8.71 x 10 m/s and a heat transfer coefficient of 2730 W/m K were measured for similar flow conditions. Calculate the ratio of the velocity in the fluid where the laminar sub-layer terminates, to the stream velocity. Molecular diffusivity = 1.5 x 10 m /s. Viscosity = 1 mN s/m. Density = 1000 kg/m. Thermal conductivity = 0.48 W/m K. Specific heat capacity = 4.0 kJ/kg K. [Pg.306]

The liquid-nitrogen flow rate was measured with a turbine flowmeter. The total pressure of the jet exhaust Ptj was measured at an orifice in the model plenum chamber by a Precision Pressure Balance transducer. The total temperature of the CO2 exhaust was measured by a thermocouple in the line leading into the vacuum chamber. This thermocouple was downstream of the pressure-regulating valve and therefore measured the total temperature of the CO2 after the expansion to near the jet total pressure. The total temperature and the total pressure of the jet were used in a one-dimensional isentropic flow equation for choked nozzles to calculate the mass flow of CO2. The specific heat ratio used was that corresponding to the total temperature and pressure of the jet. [Pg.465]

The third section of the memoir, Reflections on the theory of heat, summarized lucidly what Lavoisier and Laplace sought to accomplish with their machine exact quantitative control of the distribution and the flow of heat in a system of bodies. In order to frame a complete theory of heat, four different kinds of measurement were necessary a linear thermometer, the specific heats of bodies as a function of temperature, the absolute quantities of heat contained in bodies at a given temperature, and the quantities of heat evolved or absorbed in chemical combinations or decompositions. This is in fact an excellent summary of the directions in which the thermometric investigation of heat had proceeded until then, except for the last item, which Lavoisier and Laplace added. They could not measure all these quantities directly, however, as they readily admitted. Particularly problematic was the relationship between the thermometer readings and the absolute quantities of heat. The assumption that the ratio of absolute heats was proportional to the ratio of specific heats was very uncertain and would require many experiments for confirmation. Specific heats only indicated the difference [Pg.347]

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