Pre-mixing cryogenic fuels and using only one fuel tank












4












$begingroup$


A methalox engine is fed from two cryogenic fuel tanks. Why can't the methane and oxygen be mixed as gases, in the desired proportions, and then chilled to a temp that liquefies both? From a single tank a single turbo pump could then feed this into the combustion chamber (part of flow going thru the nozzle cooling channels). Yes, a bit of same mix would be tapped off to power the turbo pump.



Saves the weight of tank bulkheads, separate plumbing, reduces turbo pump complexities. Must be a reason or the rocket scientists would already be doing this, but would like to know what it is.






fuel







share|improve this question









$endgroup$

















    4












    $begingroup$


    A methalox engine is fed from two cryogenic fuel tanks. Why can't the methane and oxygen be mixed as gases, in the desired proportions, and then chilled to a temp that liquefies both? From a single tank a single turbo pump could then feed this into the combustion chamber (part of flow going thru the nozzle cooling channels). Yes, a bit of same mix would be tapped off to power the turbo pump.



    Saves the weight of tank bulkheads, separate plumbing, reduces turbo pump complexities. Must be a reason or the rocket scientists would already be doing this, but would like to know what it is.






    fuel







    share|improve this question









    $endgroup$















      4












      4








      4





      $begingroup$


      A methalox engine is fed from two cryogenic fuel tanks. Why can't the methane and oxygen be mixed as gases, in the desired proportions, and then chilled to a temp that liquefies both? From a single tank a single turbo pump could then feed this into the combustion chamber (part of flow going thru the nozzle cooling channels). Yes, a bit of same mix would be tapped off to power the turbo pump.



      Saves the weight of tank bulkheads, separate plumbing, reduces turbo pump complexities. Must be a reason or the rocket scientists would already be doing this, but would like to know what it is.






      fuel







      share|improve this question









      $endgroup$




      A methalox engine is fed from two cryogenic fuel tanks. Why can't the methane and oxygen be mixed as gases, in the desired proportions, and then chilled to a temp that liquefies both? From a single tank a single turbo pump could then feed this into the combustion chamber (part of flow going thru the nozzle cooling channels). Yes, a bit of same mix would be tapped off to power the turbo pump.



      Saves the weight of tank bulkheads, separate plumbing, reduces turbo pump complexities. Must be a reason or the rocket scientists would already be doing this, but would like to know what it is.






      fuel




      fuel






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked 2 hours ago









      SpaceInMyHeadSpaceInMyHead

      9116




      9116






















          3 Answers
          3






          active

          oldest

          votes


















          9












          $begingroup$

          They would stratify.



          Think of oil and water.



          Liquid oxygen is much denser than liquid hydrogen, with 1.141 g/cm3 for LOX vs. 0.07099 g/cm3 for LH.



          Thus, you need to install equipment to ensure proper mixing of the two liquids. This adds not only complexity to an already complex machinery, it also adds weight.






          share|improve this answer









          $endgroup$













          • $begingroup$
            Good answer! This is the engineering reason. "Because it won't work!"
            $endgroup$
            – Organic Marble
            1 hour ago








          • 1




            $begingroup$
            The question is about methalox. Would the same apply? Also, the mass cost/complexity of mixing needs to be balanced against the mass cost/complexity to two tanks and plumbing.
            $endgroup$
            – SpaceInMyHead
            1 hour ago










          • $begingroup$
            This document shows that the densities of liquid methane and liquid oxygen are greatly different, so yes, the same applies. engineeringtoolbox.com/cryogenic-fluids-d_492.html Oxygen is more than twice as dense as methane.
            $endgroup$
            – Organic Marble
            49 mins ago





















          7












          $begingroup$

          In addition to what the other answer said, it would take very little provocation for such a situation to turn into a good way to test the blast resistance of nearby facilities.






          share|improve this answer









          $endgroup$









          • 2




            $begingroup$
            Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
            $endgroup$
            – Tristan
            1 hour ago



















          3












          $begingroup$

          For the static fire test of AMOS-6 it is believed that the oxygen and RP1 fuel combined together due to a failed bulkhead. In this condition, only a small spark is required to cause a large explosion, as seen in the below video.











          share|improve this answer









          $endgroup$













          • $begingroup$
            Yes, but it was only an anomaly. :-)
            $endgroup$
            – SpaceInMyHead
            1 hour ago










          • $begingroup$
            Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
            $endgroup$
            – Bob Jacobsen
            41 mins ago











          Your Answer





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          3 Answers
          3






          active

          oldest

          votes








          3 Answers
          3






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          9












          $begingroup$

          They would stratify.



          Think of oil and water.



          Liquid oxygen is much denser than liquid hydrogen, with 1.141 g/cm3 for LOX vs. 0.07099 g/cm3 for LH.



          Thus, you need to install equipment to ensure proper mixing of the two liquids. This adds not only complexity to an already complex machinery, it also adds weight.






          share|improve this answer









          $endgroup$













          • $begingroup$
            Good answer! This is the engineering reason. "Because it won't work!"
            $endgroup$
            – Organic Marble
            1 hour ago








          • 1




            $begingroup$
            The question is about methalox. Would the same apply? Also, the mass cost/complexity of mixing needs to be balanced against the mass cost/complexity to two tanks and plumbing.
            $endgroup$
            – SpaceInMyHead
            1 hour ago










          • $begingroup$
            This document shows that the densities of liquid methane and liquid oxygen are greatly different, so yes, the same applies. engineeringtoolbox.com/cryogenic-fluids-d_492.html Oxygen is more than twice as dense as methane.
            $endgroup$
            – Organic Marble
            49 mins ago


















          9












          $begingroup$

          They would stratify.



          Think of oil and water.



          Liquid oxygen is much denser than liquid hydrogen, with 1.141 g/cm3 for LOX vs. 0.07099 g/cm3 for LH.



          Thus, you need to install equipment to ensure proper mixing of the two liquids. This adds not only complexity to an already complex machinery, it also adds weight.






          share|improve this answer









          $endgroup$













          • $begingroup$
            Good answer! This is the engineering reason. "Because it won't work!"
            $endgroup$
            – Organic Marble
            1 hour ago








          • 1




            $begingroup$
            The question is about methalox. Would the same apply? Also, the mass cost/complexity of mixing needs to be balanced against the mass cost/complexity to two tanks and plumbing.
            $endgroup$
            – SpaceInMyHead
            1 hour ago










          • $begingroup$
            This document shows that the densities of liquid methane and liquid oxygen are greatly different, so yes, the same applies. engineeringtoolbox.com/cryogenic-fluids-d_492.html Oxygen is more than twice as dense as methane.
            $endgroup$
            – Organic Marble
            49 mins ago
















          9












          9








          9





          $begingroup$

          They would stratify.



          Think of oil and water.



          Liquid oxygen is much denser than liquid hydrogen, with 1.141 g/cm3 for LOX vs. 0.07099 g/cm3 for LH.



          Thus, you need to install equipment to ensure proper mixing of the two liquids. This adds not only complexity to an already complex machinery, it also adds weight.






          share|improve this answer









          $endgroup$



          They would stratify.



          Think of oil and water.



          Liquid oxygen is much denser than liquid hydrogen, with 1.141 g/cm3 for LOX vs. 0.07099 g/cm3 for LH.



          Thus, you need to install equipment to ensure proper mixing of the two liquids. This adds not only complexity to an already complex machinery, it also adds weight.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 2 hours ago









          Dohn JoeDohn Joe

          43128




          43128












          • $begingroup$
            Good answer! This is the engineering reason. "Because it won't work!"
            $endgroup$
            – Organic Marble
            1 hour ago








          • 1




            $begingroup$
            The question is about methalox. Would the same apply? Also, the mass cost/complexity of mixing needs to be balanced against the mass cost/complexity to two tanks and plumbing.
            $endgroup$
            – SpaceInMyHead
            1 hour ago










          • $begingroup$
            This document shows that the densities of liquid methane and liquid oxygen are greatly different, so yes, the same applies. engineeringtoolbox.com/cryogenic-fluids-d_492.html Oxygen is more than twice as dense as methane.
            $endgroup$
            – Organic Marble
            49 mins ago




















          • $begingroup$
            Good answer! This is the engineering reason. "Because it won't work!"
            $endgroup$
            – Organic Marble
            1 hour ago








          • 1




            $begingroup$
            The question is about methalox. Would the same apply? Also, the mass cost/complexity of mixing needs to be balanced against the mass cost/complexity to two tanks and plumbing.
            $endgroup$
            – SpaceInMyHead
            1 hour ago










          • $begingroup$
            This document shows that the densities of liquid methane and liquid oxygen are greatly different, so yes, the same applies. engineeringtoolbox.com/cryogenic-fluids-d_492.html Oxygen is more than twice as dense as methane.
            $endgroup$
            – Organic Marble
            49 mins ago


















          $begingroup$
          Good answer! This is the engineering reason. "Because it won't work!"
          $endgroup$
          – Organic Marble
          1 hour ago






          $begingroup$
          Good answer! This is the engineering reason. "Because it won't work!"
          $endgroup$
          – Organic Marble
          1 hour ago






          1




          1




          $begingroup$
          The question is about methalox. Would the same apply? Also, the mass cost/complexity of mixing needs to be balanced against the mass cost/complexity to two tanks and plumbing.
          $endgroup$
          – SpaceInMyHead
          1 hour ago




          $begingroup$
          The question is about methalox. Would the same apply? Also, the mass cost/complexity of mixing needs to be balanced against the mass cost/complexity to two tanks and plumbing.
          $endgroup$
          – SpaceInMyHead
          1 hour ago












          $begingroup$
          This document shows that the densities of liquid methane and liquid oxygen are greatly different, so yes, the same applies. engineeringtoolbox.com/cryogenic-fluids-d_492.html Oxygen is more than twice as dense as methane.
          $endgroup$
          – Organic Marble
          49 mins ago






          $begingroup$
          This document shows that the densities of liquid methane and liquid oxygen are greatly different, so yes, the same applies. engineeringtoolbox.com/cryogenic-fluids-d_492.html Oxygen is more than twice as dense as methane.
          $endgroup$
          – Organic Marble
          49 mins ago













          7












          $begingroup$

          In addition to what the other answer said, it would take very little provocation for such a situation to turn into a good way to test the blast resistance of nearby facilities.






          share|improve this answer









          $endgroup$









          • 2




            $begingroup$
            Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
            $endgroup$
            – Tristan
            1 hour ago
















          7












          $begingroup$

          In addition to what the other answer said, it would take very little provocation for such a situation to turn into a good way to test the blast resistance of nearby facilities.






          share|improve this answer









          $endgroup$









          • 2




            $begingroup$
            Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
            $endgroup$
            – Tristan
            1 hour ago














          7












          7








          7





          $begingroup$

          In addition to what the other answer said, it would take very little provocation for such a situation to turn into a good way to test the blast resistance of nearby facilities.






          share|improve this answer









          $endgroup$



          In addition to what the other answer said, it would take very little provocation for such a situation to turn into a good way to test the blast resistance of nearby facilities.







          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 2 hours ago









          TristanTristan

          10.7k13755




          10.7k13755








          • 2




            $begingroup$
            Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
            $endgroup$
            – Tristan
            1 hour ago














          • 2




            $begingroup$
            Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
            $endgroup$
            – Tristan
            1 hour ago








          2




          2




          $begingroup$
          Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
          $endgroup$
          – Tristan
          1 hour ago




          $begingroup$
          Put another way: If there exists a tank of premixed liquid CH4 and LOX, I desire to be as far away as physically possible.
          $endgroup$
          – Tristan
          1 hour ago











          3












          $begingroup$

          For the static fire test of AMOS-6 it is believed that the oxygen and RP1 fuel combined together due to a failed bulkhead. In this condition, only a small spark is required to cause a large explosion, as seen in the below video.











          share|improve this answer









          $endgroup$













          • $begingroup$
            Yes, but it was only an anomaly. :-)
            $endgroup$
            – SpaceInMyHead
            1 hour ago










          • $begingroup$
            Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
            $endgroup$
            – Bob Jacobsen
            41 mins ago
















          3












          $begingroup$

          For the static fire test of AMOS-6 it is believed that the oxygen and RP1 fuel combined together due to a failed bulkhead. In this condition, only a small spark is required to cause a large explosion, as seen in the below video.











          share|improve this answer









          $endgroup$













          • $begingroup$
            Yes, but it was only an anomaly. :-)
            $endgroup$
            – SpaceInMyHead
            1 hour ago










          • $begingroup$
            Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
            $endgroup$
            – Bob Jacobsen
            41 mins ago














          3












          3








          3





          $begingroup$

          For the static fire test of AMOS-6 it is believed that the oxygen and RP1 fuel combined together due to a failed bulkhead. In this condition, only a small spark is required to cause a large explosion, as seen in the below video.











          share|improve this answer









          $endgroup$



          For the static fire test of AMOS-6 it is believed that the oxygen and RP1 fuel combined together due to a failed bulkhead. In this condition, only a small spark is required to cause a large explosion, as seen in the below video.




















          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered 2 hours ago









          PearsonArtPhoto♦PearsonArtPhoto

          83.3k16239454




          83.3k16239454












          • $begingroup$
            Yes, but it was only an anomaly. :-)
            $endgroup$
            – SpaceInMyHead
            1 hour ago










          • $begingroup$
            Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
            $endgroup$
            – Bob Jacobsen
            41 mins ago


















          • $begingroup$
            Yes, but it was only an anomaly. :-)
            $endgroup$
            – SpaceInMyHead
            1 hour ago










          • $begingroup$
            Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
            $endgroup$
            – Bob Jacobsen
            41 mins ago
















          $begingroup$
          Yes, but it was only an anomaly. :-)
          $endgroup$
          – SpaceInMyHead
          1 hour ago




          $begingroup$
          Yes, but it was only an anomaly. :-)
          $endgroup$
          – SpaceInMyHead
          1 hour ago












          $begingroup$
          Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
          $endgroup$
          – Bob Jacobsen
          41 mins ago




          $begingroup$
          Now imagine that happening orders of magnitude faster due to premixing. It’s essentially a fuel-air explosive enhanced by a factor of several thousand.
          $endgroup$
          – Bob Jacobsen
          41 mins ago


















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