Poppet with Plain Seat (IL)

A control disc valve with a flat seat.

blockType: EngeeFluids.IsothermalLiquid.DesignComponents.Poppets.PlainSeat

Poppet with Plain Seat (IL)

Path in the library:

/Physical Modeling/Fluids/Isothermal Liquid/Valves & Orifices/Spools & Poppets/Fixed Body/Poppet with Plain Seat (IL)

Poppet with Plain Seat with Moving Body (IL)

Path in the library:

/Physical Modeling/Fluids/Isothermal Liquid/Valves & Orifices/Spools & Poppets/Moving Body/Poppet with Plain Seat with Moving Body (IL)

Description

Block Poppet with Plain Seat (IL) It represents a one-dimensional movement of a control flat valve with a flat seat.

poppet with plain seat il 1

The diameter values should be determined as follows:

where

— valve diameter;
— inner diameter of the seat;
— the diameter of the valve stem on the seat side.

In the parameter Pressure acting in the flapper seat area You can set one of three options for calculating the pressure force acting in the seat area:

Constant

It is assumed that the pressure in port B affects the active area adjacent to the opening and tends to open it. The pressure in port A affects the remaining area of the seat. This assumption is valid for turbulent flow (mainly for high lift values).
Gradient

It is assumed that the pressure in port B acts on the active region adjacent to the opening and tends to open it. A linear pressure gradient (between the pressure in port B and the pressure in port A) acts on the remaining area of the seat. These assumptions give the pressure force acting on the saddle.
Transition

It is assumed that the pressure in port B acts on the active region adjacent to the opening and tends to open it. A new diameter is being introduced , linearly dependent on the flow rate :
- if the flow is laminar, then — valve diameter;
- if the current is turbulent, then — the diameter of the saddle.
A linear pressure gradient (between the pressure in port B and the pressure in port A) acts on the valve area, limited by and , and the pressure in port A applies to the remaining area.

For laminar flow, this option is equivalent to option 2, and for turbulent flow, it is equivalent to option 1. These assumptions give the pressure force acting on the valve.

The movement and speed of the rod are transmitted to the RB port.

If the check box is selected Moving body, then the block is implemented Poppet with Plain Seat with Moving Body (IL) and the body movement is simulated. In this case, the displacement and velocity of the case are transmitted to the CA port.

There are no restrictions on the displacement value in the block, but restrictions can be provided by an attached block using end stops (Translational Hard Stop).

The area of the open opening is a variable related to the movement of the valve and the movement of the body, if modeled.

Under no circumstances should the area of the opening exceed the area of the neck, determined by the inner diameter of the seat and the diameter of the stem (on the side of the seat). Sometimes it is useful to limit the hole area to a minimum and/or maximum value. The minimum area can be used to simulate a leak or a special flow hole, even when the valve is fully attached to the seat. The maximum area can be used to simulate the flow area adjacent to the opening when the valve is wide open.

The flow rate is calculated based on the movement of the valve.

The equations

If the check box Moving body removed and the body movement is not simulated, the valve lift is defined as

where

— the rise corresponding to the zero offset, the value of the parameter Lift corresponding to zero displacement;
— moving the rod in the RA port.

If the check box is Moving body If the valve body is installed and the movement is simulated, then the valve lift is defined as

where — moving the case in port CA.

The cross-sectional area of the flow corresponding to the rise , calculated as

and the hydraulic diameter is

It is assumed that this surface divides the area occupied by the liquid into two zones. One of these areas is under pressure. , and the other is under pressure , operating in the valve area. These assumptions are correct if the amount of lift is small compared to the diameter of the seat. If the rise is large, it is obvious that at some point the smallest limitation will be the area of the neck. Therefore, the cross-sectional area of the flow corresponding to the rise , there will never be less than the neck area:

The value used for , limited between and . Usually the value is it is zero, but it can be set higher to simulate the leakage rate. Meaning usually very large (for example, Inf), but a much lower value can be set to simulate an additional hole.

If the check box is Moving body removed, the volumes of liquid that are discharged to ports A and B are calculated as

where and — the value of the parameters Volume at port A corresponding to zero lift and Volume at port B corresponding to zero lift accordingly.

If the check box Moving body installed, then

Flow coefficient calculated as

where

— pressure difference between ports;
— hydraulic diameter;
— kinematic viscosity;
— the average density of the liquid.

Expense ratio calculated as

where

— maximum flow rate, parameter value Maximum flow coefficient;
— critical flow coefficient, parameter value Critical flow number.

For meaning practically does not change. For low meaning it changes linearly with the change .

A reasonable value the default is 1000. However, for holes with complex (rough) geometry, it may be smaller. 50. For very smooth geometry, it can be set to 50000.

The average fluid velocity is

The volume consumption is

where

— the cross-sectional area of the flow;
— the density of a liquid at atmospheric pressure.

If the check box Moving body if withdrawn, the volume costs in ports B and A are calculated as

where

— liquid density at port pressure B, ;
— liquid density at port pressure A, ;
— the speed of the rod in the port RA.

If the check box is Moving body installed, then

where — the speed of the case in the port CA.

The hydrodynamic force is not taken into account in this model.

Power in the port RA calculated based on the strength in port RB , the pressure force in port B acting on the seat between the diameters and , and pressure forces between the diameters and :

Power calculated using one of the three possible methods specified in the parameter Pressure acting in the flapper seat area:

Constant: It is considered permanent in the saddle area:
Gradient: between and A linear gradient is applied:
Transition: between and A linear gradient is applied in the area between and , the remaining area uses a constant :

where

If the check box Pressure force contribution on the flapper seat at zero lift removed, then for The value of power smoothly changes between 0 and the force calculated by the chosen method.

Ports

Conserving

# A — isothermal fluid port
isothermal liquid

Details

The port of the isothermal fluid corresponds to the inlet or outlet of the hole.

Program usage name

port_a

# B — isothermal fluid port
isothermal liquid

Details

The port of the isothermal fluid corresponds to the inlet or outlet of the hole.

Program usage name

port_b

# RA — stock
translational mechanics

Details

Mechanical translational port corresponding to the rod.

Program usage name

rod_flange_a

# RB — stock
translational mechanics

Details

Mechanical translational port corresponding to the rod.

Program usage name

rod_flange_b

# CA — body
translational mechanics

Details

A mechanical translational port corresponding to the body.

Dependencies

To use this port, check the box Moving body.

Program usage name

case_flange_a

# CB — body
translational mechanics

Details

A mechanical translational port corresponding to the body.

Dependencies

To use this port, check the box Moving body.

Program usage name

case_flange_b

Parameters

# Opening orientation — the direction of movement of the spool corresponding to the opening of the hole
Positive relative rod displacement opens orifice | Negative relative rod displacement opens orifice

Details

The direction of movement of the element corresponding to the opening of the hole:

Positive orientation Positive relative rod displacement opens orifice it means that the positive movement of the spool opens the hole.
The negative direction Negative relative rod displacement opens orifice this means that the negative movement of the spool opens the hole.

Values	`Positive relative rod displacement opens orifice` \| `Negative relative rod displacement opens orifice`
Default value	`Positive relative rod displacement opens orifice`
Program usage name	`opening_orientation`
Evaluatable	No

# Moving body — movable housing

Details

Check this box if you are modeling a movable enclosure.

If the flag is unchecked, it is assumed that the body is stationary.

Default value	`—`
Program usage name	`moving_case`
Evaluatable	No

# Pressure acting in the flapper seat area — method for calculating the pressure force acting in the seat area
Constant | Gradient | Transition

Details

A method for calculating the pressure force acting in the seat area.

Values	`Constant` \| `Gradient` \| `Transition`
Default value	`Transition`
Program usage name	`force_mode`
Evaluatable	No

# Pressure force contribution on the flapper seat at zero lift — the effect of the pressure force on the seat at zero lift

Details

If this option is selected, the force of pressure on the seat (between and ) is taken into account at the moment of touch. If the flag is unchecked, the force of pressure on the seat at the moment of touch is not taken into account, and the adapter hole for the force of pressure on the seat corresponds to lifting starting from which the pressure force is fully applied to the seat.

Default value	`true (switched on)`
Program usage name	`enable_pressure_force_contrubution_at_zero_lift`
Evaluatable	No

# Nozzle internal diameter (hole) — seat diameter
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

Seat diameter .

Units	`m` \| `um` \| `mm` \| `cm` \| `km` \| `in` \| `ft` \| `yd` \| `mi` \| `nmi`
Default value	`6.0 mm`
Program usage name	`seat_diameter`
Evaluatable	Yes

# Rod diameter (nozzle side) — diameter of the stem on the seat side
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

Diameter of the rod on the seat side .

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

# Flapper diameter — valve diameter
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

Valve diameter .

Units	`m` \| `um` \| `mm` \| `cm` \| `km` \| `in` \| `ft` \| `yd` \| `mi` \| `nmi`
Default value	`10.0 mm`
Program usage name	`poppet_diameter`
Evaluatable	Yes

# Lift corresponding to zero displacement — the rise corresponding to the zero offset
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

The rise corresponding to the zero offset.

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

# Lift corresponding to minimum area — lifting corresponding to the minimum area
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

Lift , corresponding to the minimum area of the passage hole.

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

# Lift corresponding to maximum area — lifting corresponding to the maximum area
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

Lift , corresponding to the maximum area of the passage hole.

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

# Volume at port A corresponding to zero lift — the volume in port A corresponding to zero lift
m^3 | um^3 | mm^3 | cm^3 | km^3 | ml | l | gal | igal | in^3 | ft^3 | yd^3 | mi^3

Details

The volume in port A corresponding to zero lift.

Units	`m^3` \| `um^3` \| `mm^3` \| `cm^3` \| `km^3` \| `ml` \| `l` \| `gal` \| `igal` \| `in^3` \| `ft^3` \| `yd^3` \| `mi^3`
Default value	`0.0 cm^3`
Program usage name	`V_a_lift_offset`
Evaluatable	Yes

# Volume at port B corresponding to zero lift — the volume in port B corresponding to zero lift
m^3 | um^3 | mm^3 | cm^3 | km^3 | ml | l | gal | igal | in^3 | ft^3 | yd^3 | mi^3

Details

The volume in port B corresponding to zero lift.

Units	`m^3` \| `um^3` \| `mm^3` \| `cm^3` \| `km^3` \| `ml` \| `l` \| `gal` \| `igal` \| `in^3` \| `ft^3` \| `yd^3` \| `mi^3`
Default value	`0.0 cm^3`
Program usage name	`V_b_lift_offset`
Evaluatable	Yes

# Transition opening for pressure force on the flapper seat — adapter hole for pressure force on the seat
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

Lift , corresponding to the adapter hole for the pressure force on the seat.

Dependencies

To use this option, uncheck the box. Pressure force contribution on the flapper seat at zero lift.

Units	`m` \| `um` \| `mm` \| `cm` \| `km` \| `in` \| `ft` \| `yd` \| `mi` \| `nmi`
Default value	`0.1 mm`
Program usage name	`lift_saturation`
Evaluatable	Yes

Flow Coefficient Law

# Maximum flow coefficient — maximum flow rate

Details

The maximum flow rate affects the flow rate/pressure drop characteristics in the orifice. For most applications, this value can be left at the default.

Default value	`0.7`
Program usage name	`C_q_max`
Evaluatable	Yes

# Critical flow number — critical flow coefficient

Details

The critical flow coefficient affects the flow rate/pressure drop characteristics in the orifice. For most applications, this value can be left at the default.

Default value	`100.0`
Program usage name	`critical_flow_number`
Evaluatable	Yes

Initial Conditions

# Initial rod displacement — initial displacement of the rod
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

The initial displacement of the rod.

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

# Initial case displacement — initial displacement of the body
m | um | mm | cm | km | in | ft | yd | mi | nmi

Details

The initial displacement of the body.

Dependencies

To use this option, check the box Moving body.

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