Heat transfer regimes

Fig. 2.6 Typical heat transfer regimes for immersion cooling with a fluorocarbon. Reprinted from Simons (1996) with permission...

Flamant, G., Fatah, N. and Flitris, Y. (1992). Wall-to-Bed Heat Transfer in Gas-Solid Fluidized Beds Prediction of Heat Transfer Regimes. Powder Tech., 69,223. 

Flik, M.I., B.l. Choi, and K.E. Goodson, Heat Transfer Regimes in Microstructures. ASME Journal of Heat Transfer, 1992. 114 p. 666-674. 

Fig. 2. Simulated yields of oxygenates (methanol and formaldehyde) vs. oxygen conversion in different heat-transfer regimes. (1) Adiabatic, T0 = 723 K (2) isothermal, T = 723 K (3) isothermal, T = 803 K (4) isothermal, T = 893 K.

Any experiment suffers to some extent from the influence of various uncontrolled factors, such as mass- and heat-transfer regimes in different parts of the reaction system, irregularity of temperature fields and flow profiles, dead spaces, poor mixing, and independent flow of reactants, wall chemistry and its variation with time, etc. Another problem is a correlation between signals received from different sensors and real values of measured physical parameters. There is a voluminous literature on this subject here we just mention the pitfalls related to the measurements of surface and gas temperatures in the course of reaction involving very active radical species. 

Typical schematics of the LHP evaporators and corresponding heat transfer regimes are shown in Figs. 2 and 3. 

FIGURE 15.89 Flow regimes, heat transfer regimes, and wall and fluid temperatures in forced convective boiling (from Collier and Thome [3], by permission of Oxford University Press). 

S. Aziz, G. F. Hewitt, and D. B. R. Kenning, Heat Transfer Regimes in Forced Convection Film Boiling on Spheres, in Proc. 8th Int. Heat Transfer Conf, San Francisco, CA, vol. 5, pp. 2149-2154, 1986. 

A typical temperature history for a metal as it is quenched in a stationary liquid bath is illustrated in Fig. 18.48. Four heat transfer regimes are revealed. Regime I depicts the temperature response from the moment of immersion to formation of a stable vapor film. During... 

Fig. 3. Schematic diagram of the various modes of two-phase flow and heat transfer regimes at a...

Keywords Contact angle Corona splashes Disintegration Disintegration limits Droplet impact Drop surface energy Heat transfer regimes Leidenfrost point Molten metal droplet impact Rupture Secondary atomization Spread Surface topography Thermal induced atomization Wettability... 

Fig. 8.2 Heat transfer regimes, as described by the classical boiling theory...

Figure 8.3 depicts the various outcomes of a droplet impacting with velocity Uq onto a smooth surface at increased surface temperatures Tw The images evidence that the relative importance of the effects governing droplet break-up depends on the heat transfer regime. 

The physical and chemical behavior of the system requires the definition of key design decision variables. For one-stage and multistage levels those decision parameters and operational variables include operational pressure and temperature, chemical reaction kinetics i.e. equilibrium or rate-limited chemical reaction), mass/heat transfer regime, phase velocity, residence time of the reactive phase and temporal operation i.e. batch, fed batch and continuous). 

---