Annular Leakage (TL)#

The Annular Leakage (TL) block simulates the flow of isothermal liquid between the round tube and the round insert. The insert may be located off-center of the tube (eccentricity) and may have different longitudinal overlap of the tube.

If the Overlap length specification parameter is Constant, the value from the corresponding field is used, otherwise the value supplied to the Overlap length upper port is used.
If the Eccentricity specification parameter is Constant, the value from the corresponding field is used, otherwise the value supplied to the Eccentricity upper port is used.

The mass flow equation [1] (1):

(1)#\[ \dot m = \frac{ \pi \cdot (R-r)^{3}\cdot (R+r)}{12\cdot\nu}\cdot\frac{\Delta p}{L}\cdot[1+3\cdot (\frac{e}{(R-r)})^{2}\cdot \frac{R}{(R+r)}+\frac{3}{8}\cdot(\frac{e}{(R-r)})^{4}\cdot \frac{(R-r)}{(R+r)}] \]

where:

\(R\) - outer radius of the annular space, [m];

\(r\) - inner radius of the annular space, [m];

\(Δp\) - differential pressure, [Pa];

\(ν\) - kinematic viscosity of the medium, [m\(^2\)/s];

\(L\) - overlap length, [m].

The mass flow equation holds only for fully developed laminar flows.

Reynolds number equation (2):

(2)#\[ Re = \frac{G\cdot d_{г}}{\mu\cdot \pi\cdot(R^{2}-r^{2})} \]

where \(d_г\) - hydraulic diameter, [m].

Hydraulic diameter for annular section (3):

(3)#\[d_{г} = D - d\]

where:

\(D\) - outer diameter of the annular space, [m];

\(d\) - inner diameter of the annular space, [m].

The overlap length parameter is equal to the minimum overlap length if the variable length simulation signal falls below the minimum value.

Law of conservation of mass (4):

(4)#\[\dot m_A+\dot m_B=0\]

Law of conservation of energy (5):

(5)#\[\phi_A+\phi_B=0\]

where:

\(\phi_A\) - energy flow at the input, [W];

\(\phi_B\) - energy flow at the output, [W].

1. Properties#

Property	Default Value	Description	Units of measurement
Overlap length specification: Constant; Variable	Constant	-	-
Overlap length	1.5e-3	Available, when `Overlap length specification` - `Constant`	m
Minimum overlap length	1e-6	Available, when `Overlap length specification` - `Variable`	m
Eccentricity specification: Constant; Variable	Constant	-	-
Inner radius	1e-2	-	m
Outer radius	1.04e-2	-	m
Eccentricity	0	Available, when `Eccentricity specification` - `Constant`	m

2. Inputs and outputs#

Parameters	Input/Output	Description	Units of measurement	Port type
Overlap length	Input	Available, when `Overlap length specification` - `Variable`	m	Automation
Eccentricity	Input	Available, when `Eccentricity specification` - `Variable`	m	Automation
Input	Input	-	-	Thermohydraulics
Outputs	Outputs	-	-	Thermohydraulics

In order to see the connection capabilities of the block, you need to to page Description of block ports

Annular Leakage (TL)#

1. Properties#

2. Inputs and outputs#

3. Sources#