In Rankine cycle there is a concept of Tm(mean temp of heat
addition)For calculating the efficiency of the cycle we
generally use
n=1-T2/T1

again Tm taking into consideration we get
n=1-T2/Tm

as T1>Tm so he efficiency will be different for same cycle.

Can anybody explain how is it possible?

Answers were Sorted based on User's Feedback

In Rankine cycle there is a concept of Tm(mean temp of heat addition)For calculating the efficienc..

in the rankine cycle
t1 is greater and t2 will be lesser in temperature.
therefore the mean temp tm will be less then t1 and greater
than t2.

hence the efficiency will be differ

 Is This Answer Correct ? 5 Yes 1 No

In Rankine cycle there is a concept of Tm(mean temp of heat addition)For calculating the efficienc..

sorry i didn't get your question...i think (1-t2/t1) is used for reversible cycle like carnot cycle...for rankine cycle
(h1-h2)/(h1-hf4) is used....

 Is This Answer Correct ? 2 Yes 1 No

In Rankine cycle there is a concept of Tm(mean temp of heat addition)For calculating the efficienc..

thanks for the reply Balajee.Yes the efficiency will differ in he two calculations.
But my question was how can there be different efficiency for a same cycle?

Can you help?

 Is This Answer Correct ? 0 Yes 0 No

In Rankine cycle there is a concept of Tm(mean temp of heat addition)For calculating the efficienc..

n(carnot)=1-t2/t1 which is an ideal cycle.and n(carnot)is grater than n(rankine)both being in ideal condition.so in question u have used a wrong formula for n(rankine)-1 equat.u cannot use this for rankine cycle.

 Is This Answer Correct ? 0 Yes 0 No

In Rankine cycle there is a concept of Tm(mean temp of heat addition)For calculating the efficienc..

Answer / hisham tariq

eff=1-(T2/T1)---------CARNOT EFFICIENCY (IDEAL CYCLE)
eff=1-(T2/TM)-------------RANKINE CYCLE EFFICIENCY

CARNOT EFF > RANKINE EFF

If you know the rankine cycle and molliers diagram there you will find turbine entry temperature (T1) and economizer entry temperaure (T4). TM is the mean of both values.

PS: eff of rankine cysle can also be calculated by
(h1-h4)/(h2-h3)
Since, h=U+PV and U=TS -PV .So h=TS ,if you plug this guy in above formula with T replaced by Tm yoy gonna get same eff

 Is This Answer Correct ? 0 Yes 0 No

In Rankine cycle there is a concept of Tm(mean temp of heat addition)For calculating the efficienc..

Answer / palash dolai

I understand the difference now.All have explained in nicely.
I thought both formula can be used for same cycle.

 Is This Answer Correct ? 0 Yes 0 No

More Mechanical Engineering Interview Questions

what is motor?

i need bhel written test question paper for the post of mechanical engineer (je)

If anybody has placement papers for igl , plz send to me as soon my exam is on 12 Jan. My mail I'd is navjot.singh800@gmail.com

I am presently working as marine engineer on ship & I wish to settle on land. So can you please suggest any short term course with 100% job guarantee?

what are "R-condition"and "T-condition" in the designation of Steels ??

what is air standard efficiency of a cycle?

what is accilaration

WHAT IS FORMULAE TO FIND THE TR CALCULATION FOR THE SCREW COMPRESSOR,RECIPROCATION COMPRESSOR,PHE CHILLER,COOLING UNIT COIL& COOLING TOWER? PLEASE SEND ME STEP BY STEP

what is the reasson after complitation of suction stroke and started comperation stroke inlet valve open for few digrees

what is the basic need for designing the bottle filling machines

what is critical temprature

Can anyone suggest me how to learn Computational Fluid Dynamics? (I am just a beginner.)

Categories
• Civil Engineering (4642)
• Mechanical Engineering (3703)
• Electrical Engineering (15783)
• Electronics Communications (2638)
• Chemical Engineering (762)
• Aeronautical Engineering (79)
• Bio Engineering (30)
• Metallurgy (95)
• Industrial Engineering (199)
• Instrumentation (2883)
• Automobile Engineering (171)
• Mechatronics Engineering (41)
• Marine Engineering (62)
• Power Plant Engineering (170)
• Engineering AllOther (1335)