This information is part of the Modelica Standard Library maintained by the Modelica Association.

Vessel Port Data

This record describes the ports of a vessel. The variables in it are mostly self-explanatory (see list below); only the ζ loss factors are discussed further. All data is quoted from Idelchik (1994).

Outlet Coefficients

If a straight pipe with constant cross section is mounted flush with the wall, its outlet pressure loss coefficient will be ζ = 0.5 (Idelchik, p. 160, Diagram 3-1, paragraph 2).

If a straight pipe with constant cross section is mounted into a vessel such that the entrance into it is at a distance b from the wall (inside) the following table can be used. Herein, δ is the tube wall thickness (Idelchik, p. 160, Diagram 3-1, paragraph 1).

Pressure loss coefficients for outlets, entrance at a distance from wall

		b / D_hyd
		0.000	0.005	0.020	0.100	0.500-∞
δ / D_hyd	0.000	0.50	0.63	0.73	0.86	1.00
	0.008	0.50	0.55	0.62	0.74	0.88
	0.016	0.50	0.51	0.55	0.64	0.77
	0.024	0.50	0.50	0.52	0.58	0.68
	0.040	0.50	0.50	0.51	0.51	0.54

If a straight pipe with a circular bellmouth inlet (collector) without baffle is mounted flush with the wall then its pressure loss coefficient can be established from the following table. Herein, r is the radius of the bellmouth inlet surface (Idelchik, p. 164 f., Diagram 3-4, paragraph b)

Pressure loss coefficients for outlets, bellmouth flush with wall

	r / D_hyd
	0.01	0.03	0.05	0.08	0.16	≥0.20
ζ	0.44	0.31	0.22	0.15	0.06	0.03

If a straight pipe with a circular bellmouth inlet (collector) without baffle is mounted at a distance from a wall then its pressure loss coefficient can be established from the following table. Herein, r is the radius of the bellmouth inlet surface (Idelchik, p. 164 f., Diagram 3-4, paragraph a)

Pressure loss coefficients for outlets, bellmouth at a distance of wall

	r / D_hyd
	0.01	0.03	0.05	0.08	0.16	≥0.20
ζ	0.87	0.61	0.40	0.20	0.06	0.03

Inlet Coefficients

If a straight pipe with constant circular cross section is mounted flush with the wall, its vessel inlet pressure loss coefficient will be according to the following table (Idelchik, p. 209 f., Diagram 4-2 with A_port/A_vessel = 0 and Idelchik, p. 640, Diagram 11-1, graph a). According to the text, m = 9 is appropriate for fully developed turbulent flow.

Pressure loss coefficients for inlets, circular tube flush with wall

	m
	1.0	2.0	3.0	4.0	7.0	9.0
ζ	2.70	1.50	1.25	1.15	1.06	1.04

For larger port diameters, relative to the area of the vessel, the inlet pressure loss coefficient will be according to the following table (Idelchik, p. 209 f., Diagram 4-2 with m = 7).

Pressure loss coefficients for inlets, circular tube flush with wall

	A_port / A_vessel
	0.0	0.1	0.2	0.4	0.6	0.8
ζ	1.04	0.84	0.67	0.39	0.18	0.06

References

Idelchik I.E. (1994):

Handbook of Hydraulic Resistance. 3rd edition, Begell House, ISBN 0-8493-9908-4

diameter	Value: Type: Diameter (m) Description: Inner (hydraulic) diameter of inlet/outlet port
height	Value: 0 Type: Height (m) Description: Height over the bottom of the vessel
zeta_out	Value: 0.5 Type: Real Description: Hydraulic resistance out of vessel, default 0.5 for small diameter mounted flush with the wall
zeta_in	Value: 1.04 Type: Real Description: Hydraulic resistance into vessel, default 1.04 for small diameter mounted flush with the wall