Patent Application
20170335798
The present invention relates to the field of igniters for initiating combustion in the combustion chambers of space vehicle engines.
Combustion chambers that do not make use of self-igniting propellant pairs require an igniter to be used to initiate combustion. Unfortunately, self-igniting propellants are more difficult to handle than non-self-igniting propellants, and it is therefore always advantageous to make use of propellants that are not self-igniting in association with an igniter.
Igniters are thus known that make use of the propellants of the engine cycle to initiate combustion in the combustion chamber. Such igniters thus enable reignitions to be performed, and they do not require specific propellants for ignition purposes.
Nevertheless, such igniters require the propellants to arrive in the igniter in gaseous form in order to ensure that combustion is stable, and they require this feed of propellants in gaseous form to be reproducible for any reignitions that might take place under conditions (in particular temperature conditions) that can be very variable and difficult to control.
Furthermore, such igniters are coupled with the engine cycle. Specifically, since the propellants injected into the igniter are taken from the propellants used for the engine cycle, the rates at which propellants are injected into the igniter thus depend on the rates at which propellants are injected into the combustion chamber for the engine cycle.
The present invention thus seeks to propose a solution that improves these aspects, at least in part.
To this end, the present invention provides a method of starting combustion in a space vehicle engine, the method comprising:
By way of example, the first propellant is liquid oxygen and the second propellant is liquid hydrogen.
In a particular implementation, after initiating combustion, the space vehicle engine is put into operation.
Typically, the pressurization of the first tank and the pressurization of the second tank are performed in succession or else simultaneously.
The invention also provides a system comprising:
the system being characterized in that the controller and the heater are configured:
By way of example, the first propellant is liquid oxygen and the second propellant is liquid hydrogen.
Typically, the controller is configured to control putting the space vehicle engine into operation after initiation of combustion by injecting the contents of the first igniter tank and of the second igniter tank into the space vehicle engine igniter.
Typically, the controller is configured to control the heater in such a manner that the first igniter tank and the second igniter tank are fed in succession or else simultaneously.
In an example:
the controller being adapted to control the opening and closing of the first and second igniter and feed valves.
The invention also provides a space vehicle including a liquid propellant engine and a system as presented above.
Other characteristics, objects, and advantages of the invention appear from the following description, which is purely illustrative and non-limiting, and which should be read with reference to the accompanying figures, in which:
In all of the figures, elements that are in common are identified by numerical references that are identical.
The system as shown comprises a combustion device 1 and a storage device 2.
The combustion device 1 has a combustion chamber 11, an igniter 12, a first igniter tank 13, and a second igniter tank 14.
The first igniter tank 13 and the second igniter tank 14 are each connected to the igniter 12 by means of valves, respectively a first igniter valve 131 and a second igniter valve 141, and they are adapted to contain propellants in gaseous form, thereby feeding the igniter 12 with gaseous propellants.
The storage device 2 has a first propellant tank 23 and a second propellant tank 24 that are adapted to contain first and second propellants, respectively.
The storage device also has a heater 25, adapted to put the first and second propellant tanks 23 and 24 under pressure so as to apply a determined pressure therein.
The structure of such a heater 25 is well known and it is therefore not described in detail. In general manner, it involves equipment comprising a heat exchanger for heating propellants such as hydrogen and oxygen, together with an inert gas such as helium that is used for putting the tanks 23 and 24 under pressure.
The system of the invention makes use of the heater 25 by connecting it to the first igniter tank 13 and to the second igniter tank 14 so as to enable them to be filled with gaseous propellants taken from the outlet of the heater 25.
The first igniter tank 13 is thus connected to the heater 25 via a first feed valve 132, while the second igniter tank 14 is connected to the heater 25 via a second feed valve 142.
The system of the invention thus establishes a connection between the igniter 12 and the storage device 2, and it makes use of already-existing elements, namely the heater 25, for filling the first igniter tank 13 and the second igniter tank 14 with propellants that are gaseous.
The system also comprises a controller 15 that is adapted to control the opening and closing of the valves 131, 132, 141, and 142.
An example of how this system operates is described below with reference to
An initial instant H0 is defined as being the starting instant of the method.
At this instant H0, the heater 25 is put into operation.
After a waiting duration ΔH0, enabling the heater 25 to reach stable operating conditions, and typically of the order of a few seconds, the first tank 23 containing a first propellant in liquid form is pressurized up to a first threshold pressure P23.
In parallel with this pressurizing of the first tank 23, the first igniter tank 13 is filled with the first propellant in gaseous form as taken from the heater 25. The controller 15 thus opens the first feed valve 132 until the temperature and pressure threshold values P13 and T13 are reached in the first igniter tank 13. Once these conditions are reached, the controller 15 closes the first feed valve 132, and the first feed tank 13 thus contains a first propellant in gaseous form under predetermined conditions of temperature T13 and pressure T13.
The igniter tanks 13 and 14 are typically of dimensions that are smaller than the tanks 23 and 24; they are thus typically filled over a duration that is shorter than the duration of pressurizing the tanks 23 and 24.
Once the first tank 23 is under pressure and once the first igniter tank 13 has been filled, the second tank 24 is put under pressure and the second igniter tank 14 is filled.
The second tank 24 containing a second propellant in liquid form is thus pressurized using the heater 25 up to a first threshold pressure P24.
In parallel with this pressurizing of the second tank 24, the second igniter tank 14 is filled with the second propellant in gaseous form as taken from the heater 25. The controller 15 thus opens the second feed valve 142 until threshold temperature and pressure values P14 and T14 are reached in the second igniter tank 14. Once these conditions have been reached, the controller 15 closes the second feed valve 142, and the second igniter tank 14 thus contains a second propellant in gaseous form under predetermined conditions of temperature T14 and pressure T14.
The second igniter tank 14 is advantageously filled while the second tank 24 is being pressurized. The filling of the second igniter tank 14 can begin simultaneously with pressurizing the second tank 24, or in a manner that is slightly offset in time. The filling of the second igniter tank 14 is advantageously performed so as to be completed before the pressurizing of the second tank 24 is completed.
The various pressure and temperature threshold values P23, P24, P13, P14, T13, and T14 are defined, in particular as a function of the natures of the propellants used, and of the characteristics of the ignition 12, or more generally of a space vehicle engine incorporating the system described.
Once the second tank 24 has been put under pressure and the second igniter tank 14 filled, the heater 25 can be stopped.
At an instant H1, a sequence of igniting combustion is started, during which the gaseous propellants contained in the first igniter tank 13 and the second igniter tank 14 are injected into the igniter 12 in order to initiate combustion.
The injection is typically performed by means of the controller 15 opening the first igniter valve 131 and the second igniter valve 141.
Insofar as the gaseous propellants contained in the first and second igniter tanks 13 and 14 are under predetermined conditions of temperature and pressure, it is possible to initiate combustion in reliable manner.
After a duration ΔH1 corresponding to the duration of the ignition sequence, and thus to initiating combustion, an engine sequence is engaged corresponding to operation of the engine that includes the system described.
The instant H1 in this implementation can thus typically be reached sooner than in the above-described implementation.
The times required for filling the igniter tanks 13 and 14 may be different or identical. Likewise, the times required for pressurizing the tanks 23 and 24 may be different or identical.
The filling of the tanks 23 and 24 and the pressurizing of the igniter tanks 13 and 14 can thus be performed successively, simultaneously, or in such a manner as to overlap. The pressurizing of the second tank 24 and the filling of the second igniter tank 14 may for example begin while the pressurizing of the first tank 23 and/or the filling of the first igniter tank 13 have not been completed, or vice versa.
The system and the method as described present several advantageous effects.
Firstly, the filling of the first and second igniter tanks 13 and 14 is performed under controlled conditions, such that the temperature and pressure conditions therein are predefined, thus ensuring that the thermodynamic conditions of the propellants used for ignition are reproducible, thereby making ignition more reliable.
Furthermore, the feeding of propellants to the igniter 12 is decoupled from the operating cycle of the engine, thus making it possible to control the ignition sequence and the engine sequence in quasi-independent manner.
Finally, the system and the method described make use of elements that are already present in a space vehicle engine, and therefore they require very few specific components, which is advantageous in terms of weight and cost.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1460126 | Oct 2014 | FR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/FR2015/052793 | 10/19/2015 | WO | 00 |
