Properties🔗

The heat exchanger is modelled as a volumetric energy source where the energy transfer between two fluid streams is based on an effectiveness, specified as a function of the mass flow rates.

$Q_t = e \left(\dot{m}_1 , \dot{m}_2 \right) \left(T_2 - T_1\right) \dot{m}_1 C_p,$

Where:

$$Q_t$$
total heat source
$$e(\dot{m}_1,\dot{m}_2)$$
effectiveness table
$$\dot{m}_1$$
net mass flux entering heat exchanger [kg/s]
$$\dot{m}_2$$
secondary mass flow rate [kg/s]
$$T_1$$
primary inlet temperature [K]
$$T_2$$
secondary inlet temperature [K]
$$C_p$$
specific heat capacity [J/kg/K]

The energy source is distributed across the cells according to:

$Q_c = \frac{V_c |U_c| (T_c - T_{\ref})}{\sum(V_c |U_c| (T_c - T_{\ref}))},$

Where:

$$Q_c$$
energy source for cell
$$V_c$$
volume of the cell [m3]
$$U_c$$
local cell velocity [m/s]
$$T_c$$
local call temperature [K]
$$T_{\ref}$$
min or max(T) in cell zone depending on the sign of $$Q_t$$ [K]

Optional entries:

• primaryInletT : sets the primary inlet temperature. If not set, the flux-averaged temperature is used
• targetQdot : the secondary inlet temperature is derived from a target heat rejection

Usage🔗

The option is specified using:

heatExchanger1
{
type            effectivenessHeatExchanger;
selectionMode   cellZone;
cellZone        porosity;

secondaryMassFlowRate   1.0;
secondaryInletT 336;
faceZone        facesZoneInletOriented;
outOfBounds     clamp;
file            "effTable";

// Optional
// primaryInletT 293;
// targetQdot   1500;
}


The two-dimensional effectiveness table is specified according to, e.g. for the table

mfr2,1 mfr2,2 mfr2,3
mfr1,1 A B C
mfr1,2 D E F
mfr1,3 G H I

the equivalent entry becomes:

(
(
mfr1,1
(
(mfr2,1    A)
(mfr2,2    B)
(mfr2,3    C)
)
)
(
mfr1,2
(
(mfr2,1    D)
(mfr2,2    E)
(mfr2,3    F)
)
)
(
mfr1,3
(
(mfr2,1    G)
(mfr2,2    H)
(mfr2,3    I)
)
)
);


Further information🔗

Tutorials

• none

Source code

History:

• Introduced in version v3.0+
• Previously known as:
• heatExchangerSource : v2212
• effectivenessHeatExchangerSource : v3.0+