Wind-US User's Guide - Keyword Reference, VORTEX

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HEAT-EXCHANGER - Heat exchanger model (block)

HEAT-EXCHANGER ZONE iz1 BOUNDARY {I1 | IMAX | J1 | JMAX | K1 | KMAX | U surface} \ [SUBSET I range J range K range] ZONE iz2 BOUNDARY {I1 | IMAX | J1 | JMAX | K1 | KMAX | U surface} \ [SUBSET I range J range K range] TEMPERATURE [GAIN] dtemp CHX cploss EXPONENT exp END HEAT-EXCHANGER

This keyword block enables the user to model the effects of heat exchangers by specifying a discontinuous change in properties across a zone boundary or portion of a zone boundary. Multiple heat exchangers may be modeled by using multiple HEAT-EXCHANGER keyword blocks.

The BOUNDARY TVD FACTOR 0 keyword option should be used for all structured zonal boundaries with heat exchangers.

The various elements of the HEAT-EXCHANGER input block are defined as follows:

HEAT-EXCHANGER

Defines the beginning of the heat exchanger keyword input block.

END HEAT-EXCHANGER

Ends the heat exchanger input block.

ZONE iz1 BOUNDARY {I1 | IMAX | J1 | JMAX | K1 | KMAX | U surface} \ [SUBSET I range J range K range] ZONE iz2 BOUNDARY {I1 | IMAX | J1 | JMAX | K1 | KMAX | U surface} \ [SUBSET I range J range K range]

These two lines define the location of the heat exchanger. The relevant zones are given by the values of iz1 and iz2, and the relevant boundaries within zones iz1 and iz2 are specified via the BOUNDARY keyword parameter.

	iz1		First zone containing heat exchanger (i.e., the zone coupled to zone iz2).
	iz2		Second zone containing heat exchanger (i.e., the zone coupled to zone iz1).

BOUNDARY specification for structured zones is done via the I, J, or K parameters. For unstructured zones, U surface is used to specify the surface ID number.

At the specified boundaries in the above zones, if the flow is leaving the zone the heat exchanger will be modeled by increasing the temperature and decreasing the pressure when passing flow conditions to the other (i.e., downstream) zone. Conversely, if the flow is entering the zone, the temperature will be decreased and the pressure increased when passing flow conditions back to the upstream zone.

The SUBSET parameter may be used to specify that the change in properties occurs only over a part of the structured zone boundary. Otherwise (and for unstructured zones), it is assumed that the change occurs over the entire boundary. The range parameters define the part of the zone boundary over which the change occurs, and take one of the following forms:

	index1 index2		Starting and ending indices in the specified direction. `LAST` may be used for the last index.
	`ALL`		Equivalent to `1 LAST`.

The starting and ending indices for the appropriate I, J, or K parameter (depending on the boundary specified) must be the same, and correspond to that boundary.

TEMPERATURE [GAIN] dtemp

This defines the temperature change across heat exchanger, dtemp, in °R.

CHX cploss EXPONENT exp

This defines the loss across the heat exchanger. The input value cploss is the static pressure loss coefficient, Δp / (ρu)ⁿ, and exp is the mass flow rate exponent, n.

See Also: TEST 18

Last updated 21 Apr 2010