PROPSAT library
General description
The purpose of the PROPSAT library is to simulate hydraulic transients in liquid rocket engines. The most important features are the following:
- Effects of compressibility and inertia on cavities and pipes.
- Calculation of concentrated pressure losses (fittings) and distributed friction.
- Bifurcation and inversion of flow.
- Heat transfer between walls and fluid.
- Simplified real properties of the fluids.
- Special components simulating valves, pumps, gas accumulators, and heat exchangers are available.
The PROPSAT library enables the following kinds of transients to be analysed:
- Valve water-hammer.
- Pipe filling water-hammer.
- Transient conditions caused by changes in the rotation speed of the turbopumps.
There are predefined properties for the following liquids (most of them are rocket propellants):
- H2O: Water.
- IPA: Isopropyl alcohol.
- MMH: Monomethylhydrazine.
- MON-1: Mixed oxides of nitrogen 1.
- MON-3: Mixed oxides of nitrogen 3.
- N2H4: Hydrazine.
- N2O4: Nitrogen tetroxide.
- UDMH: Unsymmetrical dimethylhydrazine.
- O2: Liquid oxygen.
- H2: Liquid hydrogen.
- UserDef1: User defined fluid number 1.
- UserDef2: User defined fluid number 2.
Palette of symbols
Ports description
- Fluid: This port type represents liquid flow connections.
- Shaft: This port type represents the mechanical connection, transmited power and rotational speed.
Components description
- Accumulator: Gas accumulator.
- Bound_M: Mass flow boundary condition.
- Bound_Ps: Static pressure boundary condition.
- Bound_Pt: Total pressure boundary condition.
- CheckValve: Two-way check valve.
- Col2, Col3, ..., Col10: Collectors with a given number of fluid ports (one to ten depending on the component).
- ExitValve: Controlled exit valve.
- ExpanderASA: Pressure losses that occur in an ASA expander.
- ExpanderConical: Pressure losses that occur in a conical expander.
- ExpanderSudden: Pressure losses that occur in a sudden expander.
- Filter: Pressure losses that occur in a filter.
- FlowMeter: Mass flow meter.
- Grid: Pressure losses that occur in a grid.
- Hex: Heat exchanger.
- Pipe: Cylindrical pipe divided into control volumes to take into account mass, energy, and momentum accumulation.
- PipeRect: Rectangular pipe divided into control volumes to take into account mass, energy, and momentum accumulation.
- PipeCon: Conical pipe divided into control volumes to take into account mass, energy, and momentum accumulation.
- PipeTapArea: Tapered pipe divided into control volumes to take into account mass, energy, and momentum accumulation.
- PressLoss: Pressure losses as a user input data.
- Psensor: Pressure sensor.
- Pump: Standard pump for pure liquids.
- Pump_4q: Pump working in all the zones of operation.
- Tank: Spherical tank for liquid storage (one inlet/outlet port).
- Tank1, Tank2, ..., Tank5: Tanks for liquid storage with user-defined geometry and with a given number of liquid ports (one to five, depending on the component).
- Tsensor: Temperature sensor.
- Tube: Pipe divided into control volumes to take into account mass and momentum accumulation, and heat exchange with other components.
- Valve: Two-way control valve.
- WorkingFluid: It allows the working fluid model to be set.
- ZeroLossJun: Junction without mass or energy accumulation and without pressure loss.
Satellite propulsion example
Water-hammer in a pipe line
This example shows the PROPSAT library capabilities concerning water-hammer analysis in a pipe line. The pipe component is connected to two boundary condition components: a pressure boundary condition component at the inlet and a mass flow boundary condition component at the outlet.
The following figure contains a schematic diagram of the example:
The pressure at the inlet is constant during the simulation and the mass flow at the outlet varies as a function of time, beginning with 10 kg/s at zero time it changes linearly until 0 kg/s between 0.010 and 0.011 seconds.
The following figures illustrate the evolution of the inlet mass flow, the outlet pressure, and the outlet mass flow in the pipe:
