4.28. Surge tower, surge shaft

4.28.1. SURGTW (class)

Fig. 4.28.1 Surge tower, surge shaft

Supplier type

type label	Description	active
Surgetower constant area	Storage area is independent of liquid height (pressure head)	No
Surgetower height dep. area	Storage area is a function of liquid height (pressure head)	No

4.28.1.1. Mathematical model

A surge tower or shaft or open tank (atmospheric pressure above fluid level) with constant area supplies fluid to the system according to the differential equation:

(4.28.1)\[Q=-A_{\mathrm{tw}} d H / d t\]

in which:

Q	=	Discharge from the tower to the system	[m3/s]
Atw	=	Storage surface of the tower	[m2]
H	=	fluid level in the tower	[m]

In case the area of the surge tower is a function of height the following differential equation has to applied:

(4.28.2)\[Q=-d V_{\mathrm{f}} / d t\]

in which:

Vf

=

Volume of the fluid in the surge tower

[m3]

In steady state the surge tower does not supply fluid. In that case the equation is simply:

(4.28.3)\[Q=0\]

4.28.2. Surgetower constant area

4.28.2.1. Hydraulic specifications

description	Input	unit	range	default	remarks
area	Real	[m2]	(0-500]

See also “Mathematical model” (Section 4.28.1.1).

4.28.2.2. Component specific output

Fluid level [m]

4.28.2.3. H-actions

None

4.28.2.4. Component messages

None

4.28.3. Surgetower height dep. area

4.28.3.1. Hydraulic specifications

description	input	unit	Range	default
height-area table

See also “Mathematical model” (Section 4.28.1.1).

Example of table

Table 4.28.1 Surge tower height dependent area.

height (m)	area (m2)
2.50	25.0
4.00	25.0
5.00	10.0
7.00	10.0

Fig. 4.28.2 Surge tower height dependent area

4.28.3.2. Component specific output

Fluid level [m]

4.28.3.3. H-actions

None

4.28.3.4. Component messages

None