Annular Leakage (IL)

Leakage through the annular gap between the round pipe and the cylindrical rod in the isothermal fluid network.

blockType: EngeeFluids.IsothermalLiquid.Orifices.AnnularLeakage

Path in the library:

/Physical Modeling/Fluids/Isothermal Liquid/Valves & Orifices/Orifices/Annular Leakage (IL)

Description

Block Annular Leakage (IL) Simulates leakage through an annular gap between a round pipe and a cylindrical rod in an isothermal fluid network. The position of the rod in the pipe is not necessarily concentric and the depth of its immersion may vary.

annular leakage il 1

Ports A and B correspond to the Input and output to the unit. Input ports L and E are additional ports that regulate the depth of immersion of the rod ( ) and eccentricity ( ).

Mass flow equation

The leakage mass flow rate is calculated from the equation relating the flow rate to the pressure:

Where

— the outer radius of the annular gap;
— the inner radius of the annular gap;
— port pressure A;
— port pressure B;
— kinematic viscosity of the liquid;
— the depth of immersion of the rod;
— relative eccentricity , where — eccentricity, which, depending on the mode, is a constant value or equal to the value on port * E*;
— the relative eccentricity of saturation, which is equal to for permanent holes or the value on port E for variable holes. The relative eccentricity is always in the range of 0 before 1.

If the depth of immersion of the rod in the pipe is regulated by the port L, then its value is limited from below by the parameter Minimum overlap length.

Assumptions and limitations

The pressure–flow equation used in the block is valid only for fully developed, laminar flows. The Reynolds number of the flow can be defined as .

Ports

Conserving

# A — isothermal liquid port
isothermal liquid

Details

isothermal liquid port, corresponds to the inlet or outlet of the unit.

Program usage name

port_a

# B — isothermal liquid port
isothermal liquid

Details

isothermal liquid port, corresponds to the inlet or outlet of the unit.

Program usage name

port_b

Input

# L — adjustable rod immersion depth
scalar

Details

Optional port that sets the depth of the rod immersion in the pipe.

Dependencies

To use this parameter, select the Variable overlap length checkbox.

Data types	`Float64`.
Complex numbers support	No

# E — variable eccentricity
scalar

Details

Additional port that sets the eccentricity between the pipe and the rod.

Dependencies

To use this port, select the Variable eccentricity checkbox.

Data types	`Float64`.
Complex numbers support	No

Parameters

# Variable overlap length — adjustable rod plunging depth

Details

If this box is checked, the rod plunging depth is equal to the value on the L port.

If unchecked, the rod plunge depth is constant and equal to the Overlap length parameter.

Default value	`false (switched off)`
Program usage name	`variable_overlap_length`
Evaluatable	No

# Overlap length — rod immersion depth in the pipe
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

The depth to which the rod is immersed in the pipe.

Dependencies

To use this parameter, uncheck the Variable overlap length box.

Units	`m` \| `um` \| `mm` \| `cm` \| `km` \| `in` \| `ft` \| `yd` \| `mi` \| `nmi`
Default value	`0.001 m`
Program usage name	`overlap_length`
Evaluatable	Yes

# Minimum overlap length — minimum plunging depth of the rod
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

The minimum value of the rod immersion depth in the pipe. Anything less than this value will be equated to the specified minimum.

Dependencies

To use this parameter, select the Variable overlap length checkbox.

Units	`m` \| `um` \| `mm` \| `cm` \| `km` \| `in` \| `ft` \| `yd` \| `mi` \| `nmi`
Default value	`1e-06 m`
Program usage name	`min_overlap_length`
Evaluatable	Yes

# Variable eccentricity — variable eccentricity

Details

If this check box is selected, the eccentricity value is equal to the value from port E.

When unchecked, the eccentricity value of is constant and equal to the Eccentricity parameter.

Default value	`false (switched off)`
Program usage name	`variable_eccentricity`
Evaluatable	No

# Eccentricity — displacement of the rod axis with respect to the pipe axis
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

Distance between the axis of the rod and the pipe.

Dependencies

To use this parameter, uncheck the Variable eccentricity box.

Units	`m` \| `um` \| `mm` \| `cm` \| `km` \| `in` \| `ft` \| `yd` \| `mi` \| `nmi`
Default value	`0.0 m`
Program usage name	`eccentricity`
Evaluatable	Yes

# Inner radius — rod radius
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

Rod radius, .

Units	`m` \| `um` \| `mm` \| `cm` \| `km` \| `in` \| `ft` \| `yd` \| `mi` \| `nmi`
Default value	`0.0098 m`
Program usage name	`inner_radius`
Evaluatable	Yes

# Outer radius — pipe radius
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

Pipe radius , measured from the centre of the pipe to its inner wall.

Units	`m` \| `um` \| `mm` \| `cm` \| `km` \| `in` \| `ft` \| `yd` \| `mi` \| `nmi`
Default value	`0.01 m`
Program usage name	`outer_radius`
Evaluatable	Yes