rankine cycle with reheat

Replies

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  mechky

  Supeheated steam from boiler is at high pressure when it enters first turbine. As it passes through the first turbine, pressure of steam reduces and this low pressure steam enters second turbine. So, we name the first turbine as high pressure turbine and subsequent turbine as low pressure turbine.
  It is very much obvious that low pressure turbine will come after high pressure turbine. What doubt do you have in that?
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  mechky

  Supeheated steam from boiler is at high pressure when it enters first turbine. As it passes through the first turbine, pressure of steam reduces and this low pressure steam enters second turbine. So, we name the first turbine as high pressure turbine and subsequent turbine as low pressure turbine.
  It is very much obvious that low pressure turbine will come after high pressure turbine. What doubt do you have in that?
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  Amith Gupta

  it just regulates the force of steam that gets a reaction from the turbine blades. In other words.. a H.P. turbine has a build that could manage the forces of superheated, heavily presurrized steam. Whereas, the L.P. Turbine that gets the steam after reheating it from the boiler. The reason of using this reheat and L.P.Turbine is that.. after the H.P. stage, the steam is still hot enough and also presurrized to the extent that instead of wasting, the how-much-ever power that could be taken from it is absorbed by the L.P.Turbine. It is just optimizing the heat nd pressure and not wasting it .
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  nibhani

  mechky

  Supeheated steam from boiler is at high pressure when it enters first turbine. As it passes through the first turbine, pressure of steam reduces and this low pressure steam enters second turbine. So, we name the first turbine as high pressure turbine and subsequent turbine as low pressure turbine.
  It is very much obvious that low pressure turbine will come after high pressure turbine. What doubt do you have in that?

  i want to ask that what is the specific thing in that turbine due to which it is called as high pressure...what is the specifice property of that turbine due to which it says as high pressure...if u have to develope such type of turbine that what concept u will use in this turbine...abd i want to tell u one thing more that its a question asked in interview of ISRO.
• 

  mechky

  nibhani

  i want to ask that what is the specific thing in that turbine due to which it is called as high pressure...what is the specifice property of that turbine due to which it says as high pressure...if u have to develope such type of turbine that what concept u will use in this turbine...abd i want to tell u one thing more that its a question asked in interview of ISRO.

  The constructional difference between High Pressure and Low Pressure turbine is in the size of blades. The blades of low pressure turbine are larger than that of high pressure turbine. Large blades increases the flow area so that pressure increases and same work can be obtained.
• 

  The myth buster

  The problem basically draws your attention as to why reheating is done??
  Reheating is done to superheat the steam.The superheated steam has more enthalpy content and this raises the work output of the turbine..If a single H.P turbine is used in place of one H.P and one L.P turbine,Then most of the energy of the superheated steam would go waste.Also,the quality of steam would degrade..i.e the steam shall now have lesser dryness fraction value after expansion.This would have an adverse effect on the turbine rotor blades as these conditions would initiate corrosion.
  A H.P turbine is different in construction in design than a L.P turbine.See the constructional features of the two and you will find the difference.
• 

  Ankush Sharma

  dear, we named first turbine as high pressure turbine because at first the pressure of steam that is going to enter in the turbine is very high and this pressure energy of steam is converted into kinetic energy before entering the turbine using nozzle. so,its obvious that due to this high velocity or u can say that high pressure the blades of turbine rotate at high rpm and we get more power. and the reason that we say it high pressure turbine is that the steam entering in the turbine is at high pressure.
  
  so, now LOW PRESSURE TURBINE, when the steam expands partially using first turbine or the line reaches at the saturated vapour line in T-S diagram, the steam is reheated at constant pressure. now concentrate as the the point on the saturated vapour line where line after partial expansion meet is at low level as compared to previous point of high pressure steam before entering first turbine , so the pressure after reheating is less as compared to previous pressure and we have to maintain it constant. so the pressure entering in the second turbine is low that's why is named as low pressure turbine.
  
  i hope now its clear to u, if any doubt then feel free to ask again...