Comments on heat exchanger temperatures

Discussion in 'Propulsion' started by naupigos_gr, May 11, 2012.

  1. naupigos_gr
    Joined: Feb 2009
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    naupigos_gr Junior Member

    hi

    what kind of comments i could make on this excel spreadsheet about the heat exchangers?
     

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  2. daiquiri
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    daiquiri Engineering and Design

    It looks to me like you'd like someone else to pass the university exam for you... :p
     
  3. naupigos_gr
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    naupigos_gr Junior Member

    haha yea of course
    how the hell would i know something to comment if you don't teach me with a real piece of machinery prof !!!:p

    regards
     
  4. naupigos_gr
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    naupigos_gr Junior Member

    anyway i wrote the following..

    "Parallel flow heat exchanger has an advantage when the two fluids need to be bought in the same temperature. Meaning that parallel flow heat exchanger is more efficient in transferring heat from hot fluid to cold fluid. On the other hand, counter flow heat exchanger design has three main advantages. First one, regarding the uniform temperature difference between the two fluids which results in minimization of thermal stresses throughout the exchanger. Secondly, the outlet temperature of the hot fluid is able to approach the highest temperature of hot fluid. Lastly, the uniform temperature difference produces a uniform rate of heat transfer throughout the heat exchanger"

    any comment on that?
     
  5. SheetWise
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    SheetWise All Beach -- No Water.

    Advantage over what?
    Does it really matter where I buy them?

    As opposed to transferring heat from cold to hot?

    Over what?

    How do you transfer heat if the two liquids have uniform temperature?

    If the output of the hot approaches the highest temperature of the hot, it must not be an efficient heat exchanger -- unless it's true that the two liquids have uniform temperature. But if that's true ... how do you rate efficiency?

    Uniform temperature difference between what? I thought they were uniform.
     
  6. philSweet
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    philSweet Senior Member

    perhaps some comment on the size/weight (ie cost) of the heater exchanger needed to to the job for each case?
     

  7. naupigos_gr
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    naupigos_gr Junior Member

    thanks your your reply SheetWise and philSweet.

    i will have a look again and review my conclusions!!!


    thks and best regards,

    john
     
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