1. Pressure drop prediction models
Garimella et al. (2005)
Considered parameters
Single-phase pressure gradients
Martinelli parameter
Surface tension parameter
Fluid and geometric properties
Heat and Mass Transfer Laboratory

2. Pressure drop prediction models
Garimella et al. (2005)
Void fraction is calculated using the Baroczy (1965) correlation:
Liquid and vapor Re values are given by:
Heat and Mass Transfer Laboratory

3. Pressure drop prediction models
Garimella et al. (2005)
Liquid and vapor friction factors:
Therefore, the single-phase pressure gradients are given and the Martinelli parameter is calculated:
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4. Pressure drop prediction models
Garimella et al. (2005)
Liquid superficial velocity is given by:
This velocity is used to evaluate the surface tension parameter:
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5. Pressure drop prediction models
Garimella et al. (2005)
Interfacial friction factor:
Laminar region:
Turbulent region (Blasius):
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6. Pressure drop prediction models
Garimella et al. (2005)
The pressure gradient is determined as follows:
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7. Heat transfer prediction models
Bandhauer et al. (2005)
Considered parameters
Pressure drop
Dimensionless film thickness
Turbulent dimensionless temperature Pr
Fluid and geometric properties
Heat and Mass Transfer Laboratory

8. Heat transfer prediction models
Bandhauer et al. (2005)
Interfacial shear stress:
Friction velocity is now calculated:
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9. Heat transfer prediction models
Bandhauer et al. (2005)
Film thickness is directly calculated from void fraction:
This thickness is used to obtain the dimensionless film thickness:
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10. Heat transfer prediction models
Bandhauer et al. (2005)
Turbulent dimensionless temperature is given by:
Therefore, the heat transfer coefficient is:
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