# Interface (2P-G)

**Libraries:**

Simscape /
Fluids /
Fluid Network Interfaces

## Description

The Interface (2P-G) block represents a flow connection between a two-phase fluid network and a gas network. Pressure, temperature, and mass flow rate are equal at the interface. The block does not transfer the fluid properties of each fluid network across the interface. To conserve fluid properties, ensure that the Gas Properties (G) block and the Two-Phase Fluid Properties (2P) block have corresponding settings.

The fluid at the **2P** port must remain superheated. You can use the
**Two-phase fluid superheated vapor check** parameter to choose
what action the block performs if the fluid does not meet this condition.

### Mass and Momentum Balance

The block conserves mass such that

$${\dot{m}}_{2P}+{\dot{m}}_{G}=0,$$

where:

$${\dot{m}}_{G}$$ is the mass flow rate into port

**G**.$${\dot{m}}_{2P}$$ is the mass flow rate into port

**2P**.

The port pressures are equal:

$${P}_{G}={P}_{2P}.$$

### Energy Balance

The temperature is constant between the two fluid ports. The block calculates the energy balance over the interface as

$${\Phi}_{G}+{\Phi}_{2P}={\dot{m}}_{G}\left({h}_{G}+\frac{{w}_{G}^{2}}{2}\right)+{\dot{m}}_{2P}\left({h}_{2P}+\frac{{w}_{2P}^{2}}{2}\right),$$

where:

*Φ*is the energy flow rate into port_{G}**G**.*Φ*is the energy flow rate into port_{2P}**2P**.*h*is the specific enthalpy at port_{G}**G**.*h*is the specific enthalpy at port_{2P}**2P**.*v*is the specific volume at port_{G}**G**.*v*is the specific volume at port_{2P}**2P**.*w*is the flow velocity at port_{G}**G**such that$${w}_{G}=\frac{{\dot{m}}_{G}{v}_{G}}{S},$$

where

*S*is the value of the**Cross-sectional area at ports 2P and G**parameter.*w*is the flow velocity at port_{2P}**2P**such that$${w}_{2P}=\frac{{\dot{m}}_{2P}{v}_{2P}}{S}.$$

## Ports

### Conserving

## Parameters

## Extended Capabilities

## Version History

**Introduced in R2021a**