Component 510: 'Grounded' Water or Air Split by HVACSIM+
General Description
This component models the division of a flow stream into two flow
streams. It is referred to as 'grounded' by analogy to a grounded electrical
junction: the pressure at the center of the split is a constant, entered as a
parameter. Using as inputs the pressures at the two outlets, the subroutine
calculates the pressure and mass flow rate at the single inlet and the mass
flow rates at the two outlets. The model assumes that the flow resistance
parameter is the same for all three branches. Care has been taken to ensure
that correct results are obtained even when the flow direction of one or more
flow streams is reversed.
Nomenclature
K - flow resistance coefficient
P - pressure
w - mass flow rate
Subscripts
0 - center of split
1 - inlet
2 - first outlet
3 - second outlet
Mathematical Description
w2 = sign(P0 - P2)*[(P0 - P2)/K]^0.5
w3 = sign(P0 - P3)*[(P0 - P3)/K]^0.5
w1 = w2 + w3
P1 = P0 + sign(w1)*(K/2)*w1^2
Component 510 Configuration
Inputs Description
1 P2 - pressure at first outlet
2 P3 - pressure at second outlet
Outputs Description
1 P1 - pressure at inlet
2 w1 - flow rate at inlet
3 w2 - flow rate at first outlet
4 w3 - flow rate at second outlet
Parameters Description
1 P0 - pressure at center of split
2 K - flow resistance coefficient
Reference:
1. HVACSIM+ Building Systems and Equipment Simulation Program Reference
Manual (NBSIR 84-2996)
Daniel R. Clark
United States Department of Commerce
National Institute of Standards and Technology
Gaithersburg, Maryland 20899-0001