# Result Table - Thin Orifice

The available results that are listed in the table vary depending upon the fluid phase state and upon the visible properties that you have selected. Figure 1 shows a selection of the available results for a liquid phase state. You can choose the rows you wish to display in the results table via the Set Visible Results Dialog. Figure 1: Available results for a Thin Orifice Plate. Only descriptions for the relevant results are shown in this section. If you wish to see the definition for other values click here. -- ID -- (aka User Number): All flowsheet elements have a unique number that is assigned by FluidFlow. It is not possible for the user to change this number because it is used as a unique identifier by the scripting module. Node numbering starts from 1, incrementing upwards, and pipe numbering starts from -1, decrementing downwards. Calculated Size: This is the calculated orifice size required to meet the design conditions as defined in the model when using the automatically size option. Composition Mass %: This is the fluid mass composition that remains constant throughout the element. FluidFlow determines the composition because an individual component mass balance is carried out at each node. Corner Tap Loss: The pressure loss between the upstream and downstream corner pressure tappings. Corner pressure tappings are small circular holes drilled in the pipe wall which are used for the connection of pressure-sensitive elements for the measurement of static pressures. Corner Taps are defined by the corner formed between the orifice plate and the internal diameter of the flange. D and D/2 Tap Loss: The pressure loss between the upstream and downstream pressure tappings. The position of the upstream pressure tapping is nominally equal to D and the position of the downstream pressure tapping is nominally equal to D/2 where, D is the inside diameter of the pipe. Flange Tap Loss: The pressure loss between the upstream and downstream flange pressure tappings. The position of the upstream and downstream pressure tapping is nominally 25.4 mm (1 inch) from the upstream and downstream face of the orifice plate respectively. Flow: This is the flow through the thin orifice plate that FluidFlow has calculated. Flow at NTP: This is the volumetric flow referenced to normal conditions (0°C and 101325 Pa). NTP flow is the same as the gas flows through the element. Flow at STP: This is the volumetric flow referenced to standard conditions (15°C and 101325 Pa). STP flow is the same as the gas flows through the element. Friction Loss: This is the calculated total pressure loss due to friction. In Mach Number: This is the ratio of inlet velocity to the velocity of sound at the inlet conditions. It is not possible to reach a mach number greater than 1 within this element. The velocity of sound is a thermo-physical property and depends on temperature and pressure. In Stagnation Pressure: The stagnation pressure at the orifice plate inlet. This is the sum of kinetic and pressure energies (static pressure + velocity pressure). Stagnation pressure is the pressure a flowing fluid would rise to if brought isentropically to rest, converting its kinetic energy to enthalpy. Stagnation pressure is a measure of the usefulness of the gas's energy. In Stag. Temperature: This is the stagnation temperature at the orifice plate inlet. The stagnation temperature is the temperature that the fluid would reach if it were brought to rest isentropically, converting its kinetic energy to enthalpy. In Static Pressure: This is the pressure that acts equally in all directions at a point in the fluid and is present irrespective if the fluid is flowing or if the fluid is at rest. The pressure inside any orifice plate is not the static pressure, unless there is no flow. Stagnation pressure is the flowing pressure. In Static Temperature: The static temperature at the orifice plate inlet. Static temperature is related to stagnation temperature (ignoring work, heat exchange, and potential energy) by the equation T 1 = T 1 0 - 0.5v 1 2 / C p In Velocity: The velocity at the orifice plate inlet. For liquids and gases, velocity increases as the fluid moves across the orifice plate. This can also occur with two phase flow where flashing exists, or for an incompressible fluid where the temperature rises. Joule–Thomson Coefficient: The Joule–Thomson effect describes the increase or decrease in the temperature of a gas when allowed to expand. The change in temperature (T) with a decrease of pressure (P) at constant enthalpy (H) is referred to as the Joule–Thomson coefficient (μJT). FluidFlow uses the Peng Robinson EOS to evaluate the Joule–Thomson coefficient which is expressed as: μ JT = (∂T/∂P)H The value of μJT is typically expressed in °C/bar and is dependent on the physical properties of the gas, as well as the temperature and pressure of the gas before expansion. K Value: This represents the Pressure Loss Coefficient (K) which has been automatically back-calculated by the software using the equation: K = 2 Δ P/ρ v 2 Out Mach Number: This is the ratio of outlet velocity to the velocity of sound at the inlet conditions. It is not possible to reach a mach number greater than 1 within this element. The velocity of sound is a thermo-physical property and depends on temperature and pressure. Out Stagnation Pressure: The stagnation pressure at the orifice plate outlet. This is the sum of kinetic and pressure energies (static pressure + velocity pressure). Stagnation pressure is the pressure a flowing fluid would rise to if brought isentropically to rest, converting its kinetic energy to enthalpy. Stagnation pressure is a measure of the usefulness of the gas's energy. Out Stag. Temperature: This is the stagnation temperature at the orifice plate outlet. The stagnation temperature is the temperature that the fluid would reach if it were brought to rest isentropically, converting its kinetic energy to enthalpy. Out Static Pressure: This is the pressure that acts equally in all directions at the point in the fluid and is present irrespective if the fluid is flowing or if the fluid is at rest. The pressure inside an orifice plate is not the static pressure, unless there is no flow. Stagnation pressure is the flowing pressure. Out Static Temperature: The static temperature at the element outlet. Static temperature is related to stagnation temperature (ignoring work, heat exchange, and potential energy) by the equation T 2 = T 2 0 - 0.5v 2 2 / C p Out Velocity: The velocity at the orifice plate outlet. For liquids and gases, velocity increases as the fluid flows across the orifice plate. This can also occur with two phase flow where flashing exists, or for an incompressible fluid where the temperature rises. Velocity can also decrease, for example cooling of a liquid. Stagnation Pressure Loss: This is the difference between the stagnation pressure at the inlet and outlet of the orifice plate. Static Pressure Loss: This is the difference between the static pressure at the inlet and outlet of the orifice plate. This will differ to the corner tap loss, flange tap loss, etc., as it also takes into account pressure recovery which may occur across the orifice plate. Vena Contracta Mach#: This is the ratio of the fluid velocity at the orifice plate to the local velocity of sound. Vena Contracta Velocity: The velocity level which occurs at the point of maximum convergence (minimum cross-sectional area) of the flowstream. The vena contracta normally occurs just downstream of the actual physical restriction in an orifice plate.