HXAIR - Film Coefficients

Use this window to enter details of the FILM COEFFICIENTS Window.

Usage

Film Options

Use this window to enter data for airside, tube side, and overall film heat transfer coefficient data. These data provide adjustment factors and override values for the heat transfer coefficients. All the data items in this window have default values.

Overall U-value Estimate

For rating mode the calculation of overall heat transfer coefficient is iterative. You may enter an initial estimate, which may speed up calculations.

Overall U-value Scale Factor

You may enter a multiplier, which PRO/II applies to all heat transfer coefficients, whether rigorously calculated or input on this window. Use this entry to match plant data more closely. This scale factor is applied in addition to the individual film coefficient scale factors.

Tubeside and Airside Data

You may enter data for heat transfer coefficient and fouling for each side of the exchanger.

Film Options

You may enter either a scale factor or a film heat transfer coefficient Scale Factor: Enter a factor to be applied to the rigorously calculated film coefficient for this side of the exchanger. This scale factor is applied in addition to the overall film coefficient scale factor.

Coefficient

Enter a value of coefficient to override the rigorously calculated coefficient for this side.

Fouling Resistance

This value is used to calculate the overall heat transfer coefficient. PRO/II also calculates the overall fouling resistance required to meet the specification using the defined area.

Fouling Thickness

You may enter the thickness of the fouling layer to model its effect on the pressure drop.

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