Program features:

The WAK program designs coil type economizers with multiple helical tube bundles. Water heaters or thermal oil heaters can be calculated. The standard medium is hot oil on the tube side and flue gas on the shell side. User-specific data for the flue gas can be entered or you may select standard compositions for typical gas , fuel, or solid fuel combustions.

Calculation of horizontal or vertical exchanger arrangement is possible. The flow pattern is either countercurrent or cocurrent. The program suggests parallel flow in coils and annulus.

Selectable:

1. 2 - 14 concentric tube baskets with or without a flow directing unit 
2. if the most inner or most outer basket touches the shell or displacement body or can be constructed with a gap
3. gap widths at displacement body and at shell independent from each other
4. the tube geometry and number of tubes in the coils may be freely specified.

An improved calculation of the flue gas-side heat transfer allows longitudinal pitch ratios from 1.0 on (the tubes are are narrowly coiled and welded). In the calculation, the effect of radiation from the flue gas is taken into account.

The maximum film temperature is calculated for the coil  with the lowest heat transfer coefficient and for the section with the highest temperature level.

Extensions

• Improved calculation of the actual outlet temperatures with the FN modules
• Thermal conductivities of several steels are implemented to the help file.

Physical properties

Price: 2,400 EUR plus VAT

Literature:

• VDI Heat Atlas
• F. Brandt, Wärmeübertragung in Dampferzeugern und Wärmetauschern, Vulkan Verlag 1995
• H. Hansen, Wärmeübertragung im Gegenstrom, Gleichstrom und Kreuzstrom, Springer 1976