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Rocket Propulsion Analysis | ||||
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How to define initial temperature and pressure of an propellant components?
The component on the list features 4 parameters: species name, mass fraction of the species in the component
(for bipropellant systems) or propellant (for monopropellant systems), initial temperature of the species,
and initial pressure of the species.
Initial species temperature and pressure are optional parameters. If not specified, the follwing default values will be assigned automatically:
To specify the initial temperature and/or pressure of the species, double-click on the corresponding cell,
enter the new value and then press Enter button (or click away):
To change the unit, double-click on the corresponding cell, select the desired unit on the list,
and tnen press Enter button (or click away):
The temperature can be entered using one of the following units:
The pressure is an absolute pressure and can be entered using one of the following units:
Note:
the initial temperature and/or pressure can only be specified for the components
which are supplied together with thermodynamic properties either in the polynomial form or in tabular form.
Note:
if the components change their temperature/pressure due to the work performed by components themselves, you should
assign initial (T,p) which components had before the work is performed.
How to define gaseous components (e.g. O2 and H2) as a propellant components?
Open dialog window "Components" and click the radiobutton "Show complete list of components and products of reaction".
Then choose the gaseous component you need and push the button "OK":
How to find optimum mixture ratio?
Open the screen "Propellant Specification", choose Bipropellant System, and then select the item "optimum"
on the right side of the input box "Mixture ratio":
Note: by default the program optimizes the mixture ratio for maximum estimated delivered specific impulse. To calculate the optimum mixture ratio for maximum theoretical ideal specific impulse, set both the reaction efficiency and the nozzle efficiency to 100% on the screen "Nozzle Flow Model Specification" (use the button "Efficiency" to quick jump to the screen). Note: you can also find the optimum mixture ratio using "Nested Analysis Tool". Just run it for the ranhe of mixture ratio and plot the results. How to define 3-components propellant system using bipropellant system configuration?Assume we need to specify propellant which consists of one oxidizer component and two fuel components. Choose bipropellant system, then define mixture ratio, which is the ratio of oxidizer mass flow rate to the sum mass flow rate of both fuel components. Add the oxidizer component on the oxidizer list. Then add two desired fuel components on the fuel list. Specify mass fraction of each fuel component within the fuel, that is the sum of each of mass fractions on the fuel list has to be equal to 1. How to define 3-components propellant system using monopropellant system configuration?Assume we need to specify propellant which consists of one oxidizer component and two fuel components. Choose monopropellant system. Add the oxidizer component on the propellant list. Then add two desired fuel components on the same list. Specify mass fraction of each component, that is the sum of each of mass fractions on the propellant list has to be equal to 1. What is the difference between bipropellant and monopropellant systems?
For the thermodynamic calculation, the only difference between bipropellant system and monopropellant system that contains two species,
is how the species mixture is defined. Actually, you may define any bipropellant system
(as well as three- or more propellant systems) as a monopropellant system, specifying the proper mass fraction for each
component on the list.
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Copyright © 2009-2012 Alexander Ponomarenko
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Last modified: May 9, 2012
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