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Super Heated Implosion Jets

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  • Super Heated Implosion Jets

    Do to the popularity of this article, I thought I'd invite everyone to continue the conversation on the forum:

    What are your thoughts on this topic?

  • #2
    Response from Tom Mallard:

    "It’s called cavitation erosion, generally,"


    • #3
      Response from Ken in SoCal:

      "Cavitation voids are not air bubbles and are more damaging than entrained air bubbles. The cavitation “bubble” is a vacuum pocket created when the line pressure drops below the partial pressure of water at the temperature of the water – Same idea as boiling water at room temperature, if you pull a vacuum on it.. When the line pressure is increased in the pump, the vacuum pocket slams closed and can result in surface damage. Cavitation has been shown to create hydroxide radicals, which is a highly oxidative species. In contract, as an air bubbles passes through a pump, it does not slam close because it was not a pocket of vacuum. Instead, it just compresses. Thus, it does not damage pump surfaces as cavitation does."


      • #4
        Response from William Grissom:

        "I understand cavitation to be the generation of bubbles of vapor, not air coming out of solution. The vapor is generated when the pressure falls below the saturation pressure (at the current temperature). Certainly air will also come out of solution as pressure falls, but cavitation can occur in water which has no dissolved air. A cavitation bubble violently returns to a liquid as the pressure increases, indeed some Physicists predict that event is a “singularity” that could in some theoretical approximations release enough energy to cause nuclear events, or at least generate visible light. That may be the mechanism which causes damage to metal surfaces. However, just having the large density differences between gas and liquid could also cause damage as a fast-moving metal surface interacts, so air bubbles may be bad as well. I think this is still a research area. I don’t think air bubbles quickly re-dissolve in the water and can linger a long time once they come out of solution. Re-dissolving certainly isn’t a violent event as a cavitation bubble collapsing is."


        • #5
          Response from Linas Repecka:

          "The term used for collapsing bubbles which cause damage is, indeed, ‘cavitation’. It refers to both the creation and collapse of bubbles, which is why you have not heard of any other term for the collapse part. Your argument is like saying no one dies from falling, they die from hitting the ground. Also, they are not ‘air’ bubbles. Air in the bubbles cushions the collapse and makes the process non destructive. Cavitation is the creation of a cavity in a fluid due to turbulence and fluid inertia."


          • #6
            Response from Steven Johns:

            "“Cavitation is the creation of air bubbles; that’s it.” Air bubbles? While you are correct in stating that it is the collapse of the bubbles against the surfaces that cause damage, saying that cavitation is the creation of air bubbles ranks right up there with those that say Nuc-u-lar……."


            • #7
              Response from David Shaddock (I love this one ... "Imruption" has my vote so far LOL):

              " Wait–little bubbles created from vacuum? I thought they came from dissolved gas that comes out of saturation when the pressure drops in the liquid…
              But I think you might consider ‘imruption’ for the implosion of superheated jet. It’s kind of the reverse of an eruption.
              Nice article–I love clear explanations (that I can then borrow to edify other engineers!)."


              • #8
                Response from Tom Gartian"

                A different perspective.
                Scan to about 32:00 and 40:00 of this video."


                • #9
                  Response from Kevin Nash:

                  "How about “fluid ping” for a name?"


                  • #10
                    Responses from Francis X Gentile:

                    " “Re-Pressurized bubble implosion super-heated jet” ? Jet seems to imply it is going in one direction as in a shaped charge, but the bubble is going in all directions? so it would be “Re-Pressurized bubble implosion super-heating”?
                    you had me for a moment with the exhintake thing, since I have 2 patents on feeding fuel into engines from the exhaust side, but I see the idea is to use an exhaust cam as an intake cam as a cheap custom intake cam."

                    "Could it be that the low pressure side of the pump and the high pressure side of the pump is enough on the same side of a proppellor wing section that the full cycle of reduced pressure bubble creation and “Re-Pressurized bubble implosion super-heating” could occur during the flow.. across the cambered lifting side of the blade {wing]. Creation might occur around 25 percent chord and erosion further towards the trailing edge? Or upstream bubbles could be pressurized by the leading edge and erosion could occur there? As an non expert I head about cavitation on giant ship and submarine proppellors so that might be the origin of bubble creation and implosion being created in the same area an being labled with the one word associated with the first step, which can occur elsewhere prior."


                    • #11
                      Francis, yes, it's just a cheap modification to use an exhaust cam as an intake cam. However, it was still my invention, and I'm proud the Mazda community has taken flight with it. Sorry for being off-topic. LOL


                      • #12
                        "Implosion" must be the keyword for cavitation. Implosion can only occur when a low-pressure vacuum bubble get hit by higher pressure. The cavitating power induced must be a function of the level of vacuum pressure, the size of vacuum bubble and the time of re-pressurization. I would also suggest that there will be more cavitation damage if fluid density is higher.
                        Vacuum pressure is relative to atmospheric pressure. Atmospheric pressure is about 1 bar, and absolute vacuum is 0 (zero) bar. I would also suggest that higher displacement pumps tend to cavitate more than the lower displacement pumps.
                        If an air bubble enters the suction side it can not by it self, induce cavitation when pressurized since there won't be an implosion. An air bubble that is part of negative pressure (close to vacuum) on the suction side will make it impossible to create a full vacuum (ie 0 bar absolute pressure) in the bubble.
                        I can not see how air bubbles can be part of cavitation unless they are set under negative pressure. And then the negative pressure can never become as low as if there was no air in the bubble. But a lot of air in the fluid will for sure make wear damage due to lower lubrication.
                        "How do you like them apples?"....
                        Last edited by akkamaan; 02-13-2016, 01:36 AM.


                        • #13
                          Ok, so we know what cavitation is. Under what conditions does cavitation occur in a cylinder? This is probably better answered in a separate thread.


                          • #14
                            Originally posted by Peter Nachtwey View Post
                            Ok, so we know what cavitation is. Under what conditions does cavitation occur in a cylinder? This is probably better answered in a separate thread.
                            ...perhaps a new thread would be good. You do that, and then I'll pipe up in it! :P