Scientists announced a solution to the problem of long-term testing of rocket engine models


Under the heading “Let's talk about science”, the topic of research aimed at reducing the time of testing models of rocket engines is proposed for discussion.


The essence of the problem for developers is that they spend enormous resources, including time and finances, for testing engines designed for the rocket industry. Almost any change made to the engine design requires a new process for conducting test tests, which is not always possible due to a variety of circumstances.

It would seem that computer technologies come to the rescue, allowing to simulate test processes for rocket engines. But here, not everything is simple.

A group of researchers from the University of Texas (USA) published a report stating that even with a supercomputer, satisfactory test data can be obtained only a few weeks after the start of the computer simulation process. An example is the analysis of the SpaceX Merlin rocket engine. The work on modeling the workflow of its latest version was carried out for several months, which did not satisfy either the customers or the modeling specialists themselves.

The head of the research group, Karen Willcox, reports on the development of new methods of “scientific machine learning” to accelerate the testing process, to solve the problem of the duration of this testing. This is a method that combines scientific computing with machine data, including using physical modeling. The new approach, says Dr. Willcox, takes the opportunity to reduce the size of the power plant during the simulation, significantly reducing testing time.

When creating rocket engines, it is important for engineers to receive timely data on how not the entire installation will behave, but its specific unit, assembly. When taking into account one or another of its design, when making changes to this design. Using the method of machine analysis of a reduced propulsion system is not always possible, but to obtain key results it can be applied and transmitted to designers, according to representatives of the research group.



In particular, a new method using "machine learning" was used to calculate the parameters of fuel combustion in the engine chamber. Using a computer model, specific scenarios were obtained during the operation of the injector. Based on the analysis of these scenarios, graphs of pressure fields, velocity, chemical composition of the combustion products, and their temperature were created. In turn, these data helped researchers create a model of the reduced-order engine, as well as “train the computer” to perform accelerated analysis.

Scientists themselves call the method - from particular to general through intermediate data.

From the report:

This version of the work made it possible to generate results with subsequent computer processing for about two hundred hours. The machine, on the basis of the experience gained, now proceeds to "self-learning" to speed up the analysis procedure. This is a kind of repetition of processes on the simulator. It is planned that with the improvement of the process, an analysis of the operation of the rocket engine can take only a few seconds.

Dr. Willcox:

Of course, this method will not solve multilevel problems of testing rocket engines. But at the first stage, it will definitely allow you to save resources on the analysis of basic data, reduce the process time, ensuring high results.


For reference: SpaceX Merlin rocket engine refers to liquid. It has several modifications, including Vacuum 1D. Weight - up to 500 kg. Thrust under conditions of gravity at sea level is approximately 850 kN. Operating time - up to 375 s (depending on version). The pressure in the combustion chamber is 97 atm. First used at launch in September 2013.
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  1. sanik2020 April 20 2020 09: 57 New
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    Under the heading “Let's talk about science”, the topic of research aimed at reducing the time of testing models of rocket engines is proposed for discussion.

    And here is that, a specialized forum of rocket engines.
    -I got here or not here.
    1. knn54 April 20 2020 10: 31 New
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      Posted on Monday after Easter?
      Brezhnev is standing in front of the mirror:
      - The idea ...
      - The idea ...
      - I am the idea?
      1. mole April 20 2020 10: 52 New
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        Here's another:
        A man wakes up in the morning, looks around, gets up, goes to the mirror and gazes intently into the reflection.
        Then his wife came to him from the kitchen: "Seryozha, go have breakfast!"
        A man to his reflection: "I remembered! Sergey!" drinks
    2. gridasov April 20 2020 10: 35 New
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      And who's stopping you from passing by? Or is this not a fundamental topic of improving the country's defense
  2. Thrifty April 20 2020 10: 01 New
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    Actually, all these computer programs have one problem - the notorious human factor. One error in the calculation program initially gives a greater measurement error, and calls into question the creation or testing of the product in the future. Therefore, no matter how expensive and difficult the full-scale tests were, one cannot do without them for another decade.
  3. Yrec April 20 2020 10: 03 New
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    If we are talking about an engine on a military missile with a one-way ticket, then you can use this method, if the engine "carries" people, then no. Until the product passes the full test cycle, you should not trust it. No models and layouts will not work.
    1. U-58 April 20 2020 10: 33 New
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      Far from it.
      If a missile is military with a one-way ticket, then “failure to fulfill a combat mission” leads to the trial of a military tribunal. So the responsibility in all cases is high (((((
  4. Operator April 20 2020 10: 03 New
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    100 atmospheres in the combustion chamber is about nothing laughing
    1. Thrifty April 20 2020 10: 07 New
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      Operator hi is a super grill, chicken to fry, or barbecue lol !!!
    2. gridasov April 20 2020 10: 38 New
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      The problem of raising pressure by orders of magnitude is solved very simply. It is necessary to change the short duration of the process, so to speak, and this is achieved technically
      1. Bobrick April 21 2020 21: 30 New
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        In the sense, to organize faster combustion or replace the continuous combustion process with a pulsating one?
        1. gridasov April 22 2020 11: 02 New
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          Both! but more! It must be understood that in order to avoid the continuity of the process and the discontinuity of the flow, it must be ensured that both the inlet and the inlet flow are inseparable. This is a technology for providing algorithms for individual stages. Etc
    3. Errr April 20 2020 10: 56 New
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      Quote: Operator
      100 atmospheres in the combustion chamber is about nothing laughing
      In what sense is "about nothing"? "Unions" are still flying with the help of RD-107. The latter has a pressure of "only" 58 atm in the combustion chamber. smile
      1. Operator April 20 2020 12: 39 New
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        RD-107, after all, turned 63 years old, despite the fact that the super-duper Merlin is actually listed as a Mask in the category of innovation.

        With this approach, the RD-180 with 253 atmospheres for staff members should go through the category “give true fantasy” laughing
        1. Errr April 20 2020 15: 19 New
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          I don’t know what category the RD-180’s “staffers” pass there, but what’s just 5 (!!!) single chamber F-1, installed on the first stages of Saturn V, with pressure in their combustion chambers "just in some" 69 atm 7 times "shot" to the moon for 2965 tons of lunar expeditions of full equipment (and at the same time not a single failure!) I personally cause genuine delight and admiration.
          And no more about big pressures in the combustion chamber, I beg you. hi
          1. Operator April 20 2020 16: 27 New
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            Do not post your comments to mine.
        2. Blackmokona April 20 2020 16: 45 New
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          It is considered innovative due to its low durability, ease of production, and its large resource.
          1. Operator April 20 2020 17: 22 New
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            Kerogas also has a low cost, ease of production and a large resource laughing

            The design of Merlin was developed by order of NASA back in the Old Testament times (hence the pressure of 100 atmospheres), rejected and laid out for free access in accordance with American laws (like all unclassified products designed for budgetary funds). Musk just picked up what no one needed.

            Admittedly, the miscreant Herrr was babbling something about the Saturn’s hydrogen-oxygen digester with even less pressure in the combustion chamber. This engine’s high hydrogen calorific value compensated for the decrease in specific impulse due to lower pressure in the combustion chamber, and most importantly, that engine was used at the second stage of Saturn, which began to work when the launch vehicle was raised into rarefied atmospheric layers, where the back pressure at the nozzle exit the order is less than at sea level.

            But even here the USSR was able to wash the Americans with the help of a hydrogen-oxygen engine RD-0120 with a pressure of 220 atmospheres installed on the Energia rocket bully
            1. Blackmokona April 20 2020 18: 29 New
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              Marilyn was developed by SpaceX, he did not use any engine as a basis, it is a completely original development for the needs of SpaceX
              Pressure is determined that SpaceX chose an open circuit to reduce the cost and simplify the engine
              1. Operator April 20 2020 19: 20 New
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                An open circuit with the discharge of exhaust gas from the turbogenerator into the external space does not affect the pressure in the combustion chamber.
                1. Blackmokona April 20 2020 19: 38 New
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                  Affects and very much.
                  Look at the pressure of engines with open circuit and closed
                  In a closed-circuit engine, the flow rate of the working fluid through the TNA turbine is significantly higher than in an open-circuit engine, which makes it possible to achieve higher pressures in the combustion chamber
                  1. Operator April 20 2020 19: 41 New
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                    Just an open-circuit rocket engine is a very ancient design, in which the pressure in the combustion chamber is also outdated.
                    1. Blackmokona April 20 2020 20: 07 New
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                      The choice between an open and closed circuit rocket engine is a matter of choosing priorities. Both engines are developed and used to this day.
                      For example, an open circuit rocket engine volcano for Arian-5 rockets was created in 1997.
                      Or the same Marilyn 2006 release.
  5. Fedorov April 20 2020 10: 23 New
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    There is clearly not a topic on the site. Roma Banshee missed or Vadim Smironov, rather wards.
    Not physicists gathered here on the site, although many with experience.
    1. lucul April 20 2020 10: 43 New
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      There is clearly not a topic on the site. Roma Banshee missed or Vadim Smironov, rather wards.
      Not physicists gathered here on the site, although many with experience.

      It’s for broadening one’s horizons - in an accessible language, everything is stated, without cleverness.
  6. The comment was deleted.
  7. U-58 April 20 2020 10: 29 New
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    All this is extremely interesting.
    It’s just not reported if there was a method check ??
    Do electronic data interfere with practical results. And what is
    statistics collected?
    1. gridasov April 20 2020 10: 53 New
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      They cannot be docked because modern methods of working with big data do not allow taking into account not only the dominant aspects, but also the very process of changing all these individual data
      1. U-58 April 20 2020 11: 48 New
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        Yeah ... There is something and how to get into the source, then you get it. Real life is richer ...
        1. gridasov April 20 2020 11: 58 New
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          Correctly you noticed! The analysis technique itself should include the constant input of new data and continuous analysis on variable processes. But, all this is not close!
      2. T.Henks April 21 2020 10: 00 New
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        Into a stomp! Now for sure no one will understand anything! Set off in full.
    2. Bobrick April 21 2020 22: 01 New
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      In areas where real data of real tests have been obtained, modern computer simulation packages give very accurate results even without machine learning (test data are used to correct the physical and mathematical models, and further - the more different statistics, the more accurate the model in known areas and in between between them, just now it can be done automatically, using machine learning).
      Yes, yes, what gridasov wrote about is being implemented in reality (only by people, manually), but even with this approach, prototypes and tests are needed (maybe fewer, but required).

      It is worth going beyond these limits, the result may be very far from practical.
  8. gridasov April 20 2020 10: 32 New
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    Many turn a finger at the temple in my address. But without using the function of a constant value of the number, it is impossible to describe not only turbulent or plasma processes, but it is necessary to analyze at each point of the local process, but laminar processes cannot be described. At the same time, attempts to build local spaces on transients look ridiculous, not to mention the highly potential ones. Moreover, small-scale engine models differ from real full-scale ones in that, from a mathematical point of view, one aggregate capacity of big data cannot be replaced by another. Is this anyone who understands? Moreover, the key problems of rocket and process-controlled engines are turbo-supercharger fuel in which the mechanism for controlling the flow of liquids or gases has the same turbulent flow limits. Hence the inability to raise the energy density, if I may say so, and this implies the impossibility of creating heavy missiles.
    1. lucul April 20 2020 10: 42 New
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      Many turn a finger at the temple in my address.

      I do not twist ....
      1. gridasov April 20 2020 10: 49 New
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        Thanks! I believe. In general, I understand that I am not the only one filled with rational and sound ideas and developments. The problem is in the mechanism of their implementation.
    2. U-58 April 20 2020 11: 50 New
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      But we are talking not only about gas-dynamic processes, but also about the work of iron, which is of great interest.
      1. gridasov April 20 2020 12: 06 New
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        Absolutely right! I sometimes miss these aspects. And of course, analysis of the whole complex of combined components involved in the process is necessary. Undoubtedly, high potential outflow of mobile flows causes ionization of the outflow surfaces and polarization of structural elements. This means that magnetic fluxes begin to form magnetic interactions in the joints and the structure of the parts and the entire structure. But this analysis does not produce measurements of various dimensions and polarization of elements now - there is no methodology. Therefore, it is obvious and there is no model taking into account the conditions of different levels of the external environment in which the engine will operate. In general, without new mathematical methods of analysis, there is no development of a strategically important industry.
    3. Amateur April 20 2020 12: 58 New
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      Comp does not calculate the engine, but its mathematical model (MM). But how much MM corresponds to a real "iron" engine is a big question. Therefore, to ensure the reliability of real hardware without real fire tests will not be possible sooooo long.
  9. voyaka uh April 20 2020 13: 00 New
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    Computer modeling gradually enters all areas of technology and science.
    Back in the mid-90s, I myself heard how doctors of chemistry in chemistry declared that comp. modeling will NEVER replace "real" creative work with test tubes in organic synthesis. Even as a substitute! In a few years.
    Today, no one will pick up the test tube until there is no computer model.
    1. gridasov April 20 2020 14: 45 New
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      You are deeply mistaken! The mathematical model of analysis 0 as it was not and never is! Why? Because MM considers only statistics and the analytical conclusions are made by the human brain. Therefore, there are no advisory aspects of the methodology. A person chooses the work of his brain and then only the probability of what can be obtained in vitro. Once again - not a single MM gives advisory and reasonable conclusions. Calculation and analysis are fundamentally different phenomena.
    2. T.Henks April 21 2020 10: 12 New
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      Very interesting. Perhaps that is why spring does not come. I look at the same MM in meteorologists and I see a wonderful window in three days that moves to the right on the timeline. With a setting two days in advance. And according to the old grandfather's forecast, the lodge will be warm until mid-May. And the summer will not please.