Flow measurement specific heats ratio

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. 

For known values of the parameters in the kinetic equation for a specific reactive mix, it is easy to calculate the dimensionless factors y and v. Then the flow pattern in the mold filling process is completely determined by the dimensionless Da and Gz Numbers and the boundary conditions. The Damkohler Number characterizes the ratio of the rates of chemical reaction and convective heat transfer and the Graetz Number is a measure of the ratio of the convective heat flux due to a moving liquid to the heat flux due to the conductivity of the liquid. 

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 10-6 m/s and a heat transfer coefficient of 2730 W/m2K 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 9 m2/s. Viscosity = 1 mN s/m2. Density = 1000 kg/m3. Thermal conductivity = 0.48 W/m K. Specific heat capacity = 4.0 kJ/kg K. 

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... 

In order to determine the j factor on the unknown side, the exchanger effectiveness e is determined from the temperature measurements, and the heat capacity rate ratio C is determined from individual flow measurements and specific heats. NTU is subsequently computed from the appropriate e-NTU relationship for the test core flow arrangement (such as Eq. II. 1 in Table 17.6). Generally, the test section is a new exchanger core, and fouling resistances are negligible T 0hA on the unknown side is determined from the following thermal resistance equation where UA is found from NTU ... 

The heat flow rate (Q) of a gaseous fuel is calculated as the product of its volumetric flow rate at standard conditions (V0) and its calorific value (CV). The Wobbe index (WI) measures the ratio between the net CV and the square root of specific gravity (SG). With orifice-type flow sensors, the advantage of detecting the WI is that it eliminates the need to separately measure the specific gravity this is because the product of the WI and orifice pressure drop results in a constant times the heat flow rate (KxQ), without requiring a separate measurement of SG. 

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