Inside film heat transfer coefficient

Inside film heat transfer coefficient 496 INSINGER, T. H. 486, 492, 564 Institution of Chemic al Engineers 516 Instruments, capillary tube viscometer 196... 

For non-Newtonian liquids and suspensions, an apparent viscosity is determined using correlations which include power input and the Reynolds number. Scale-up comparisons based on heat generation data only were determined by comparison of results from RC1 experiments and from a 675-liter reactor [208]. In the experiments, a Bingham plastic fluid was used to determine the film heat transfer coefficient. This presents a worst case because of the low thermal conductivity of the Bingham plastic. Calculated inside film heat transfer coefficients determined in the RC1 tests were about 60% lower than the values determined in the pilot plant reactor, even though substantial effort was made to obtain both geometric and kinematic similarity in the pilot reactor. 

The inside film heat transfer coefficient (h ) can be calculated from the following Nusselt number correlation ... 

Empirical dimensionless group correlations have been used in the scale-up process. In particular, the correlation for the inside film heat transfer coefficient for agitated, jacketed vessels has been employed for the scale-up to a larger vessel. Reaction calorimeters are often used to give some indication of heat transfer coefficients compared to water in the same unit. Correlation for plant heat transfer is of the general form... 

A commonly used method of determining numerical values for the inside film heat transfer coefficient for agitated, jacketed vessels is the Wilson plot. A Wilson plot (Figure 4.19) is essentially a linear regression through data points, which represent the reciprocal overall heat transfer coefficient against the reciprocal agitation speed ... 

Estimate outside and inside film heat transfer coefficient. 

Figure 10-50C. Tube-side (inside tubes) liquid film heat transfer coefficient for Dowtherm . A fluid inside pipes/tubes, turbulent flow only. Note h= average film coefficient, Btu/hr-ft -°F d = inside tube diameter, in. G = mass velocity, Ib/sec/ft v = fluid velocity, ft/sec k = thermal conductivity, Btu/hr (ft )(°F/ft) n, = viscosity, lb/(hr)(ft) Cp = specific heat, Btu/(lb)(°F). (Used by permission Engineering Manual for Dowtherm Heat Transfer Fluids, 1991. The Dow Chemical Co.)...

Figure 10-50D. Tube-side (inside pipes or tubes) liquid film heat transfer coefficient for Dowtherm A and E at various temperatures. (Used by permission Engineering Manual for Heat Transfer Fluids, 1991. The Dow Chemical Co.)...

An air stream at approximately atmospheric temperature and pressure and containing a low concentration of carbon disulphide vapour is flowing at 38 m/s through a series of 50 mm diameter tubes. The inside of the tubes is covered with a thin film of liquid and both heat and mass transfer are taking place between the gas stream and the liquid film. The film heat transfer coefficient is found to be 100 W/mzK. Using a pipe friction chan and assuming the tubes to behave as smooth surfaces, calculate ... 

A jacketed reaction vessel containing 0.25 m3 of liquid of density 900 kg/m3 and specific heat 3.3 kJ/kg K is heated by means of steam fed to a jacket on the walls. The contents of the tank are agitated by a stirrer rotating at 3 Hz. The heat transfer area is 2.5 m2 and the steam temperature is 380 K. The outside film heat transfer coefficient is 1.7 kW/m2 K and the 10 mm thick wall of the tank has a thermal conductivity of 6.0 W/m K. The inside film coefficient was 1.1 kW/m2 K for a stirrer speed of 1.5 Hz and proportional to the two-thirds power of the speed of rotation. Neglecting heat losses and the heat capacity of the tank, how long will it take to raise the temperature of the liquid from 295 to 375 K ... 

Film heat-transfer coefficient inside a tube... 

These re.si.rtflnces include the inside-the-jacket film heat-transfer coefficient (HTC) and fouling factor, the inside-the-reactor HTC and fouling factor, and the reactor-wall resistance. Assuming U, M, Cp and A are con-... 

Film heat transfer coefficient inside a tube Inside film coefficient in Boyko-Kruzhilin correlation... 

Forced-circulation-type evaporator. The liquid-film heat-transfer coefficient can be increased by pumping to cause forced circulation of the liquid inside the tubes. This could be done in the long-tube vertical type in Fig. 8.2-lc by adding a pipe connection with a pump between the outlet concentrate line and the feed line. However, usually in a forced-circulation type, the vertical tubes are shorter than in the long-tube type, and this... 

Film heat transfer coefficients may be estimated from flow conditions 2tnd from physical properties. For forced convection and turbulent flow (i.e. conditions prevailing inside stirred tank reactors), the relation... 

Outside film heat transfer coefficient = 267 W7m K (from previous plant operating data), and fouling coefficient on inside = 2500 W7m K. 

The overall heat transfer coefficient, U, is a measure of the conductivity of all the materials between the hot and cold streams. For steady state heat transfer through the convective film on the outside of the exchanger pipe, across the pipe wall and through the convective film on the inside of the convective pipe, the overall heat transfer coefficient may be stated as ... 

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