Mechanical Engineering Thermodynamics - Lec 10, pt 2 of 2: Example - Entropy Generation Heat Exch

[@川普-s9m]

Your lecture so simple, clear and rational!

[@RhizonXXVII]

So concise! Thank you.

[@ytaelshamy5090]

thanks

[@ibrahimkuru3910]

explained well

[@agusmanmayuddin6993]

thanks mr ron

[@bankingpreparation8610]

thanks so much .......

[@valentinfinozzi9358]

1. cp has the same units as specific entropy, ( kJ/(kg*K) ) if you multiply it by the flux of mass ( kg/s ) you get [ kJ*kg/(kg*s*K) ] = [ kJ/(s*K) ] . And a Juole per second is a watt so we end up with [ kW/K ].
or
2. S' is the rate of change of entropy, so you take the units for entropy derive/divide by time, and do the same reasoning of point 1.
Watts give the idea of power used/produced by a machine but this is not the case here, nonetheless the very definition of Watt is Joule/second so it is correct to use W/K for S'.

[@ilikechocolate3741]

5:03
Why is that?
Why is [KJ/(Kg*K)] the same as [KJ/(Kg*°C)?
shouldn't it be a difference??

[@ilikechocolate3741]

I confirmed that in this website:
converter.eu/heat_capacity/#1_Kilojoule/Kilogram_%C2%B0C_in_Kilojoule/Kilogram_K
But I don't get it, because when you divide by Kelvin, you are dividing for a bigger number, and as far as I know, you can't really divide by °C, because is too risky

[@i_trixngle_i]

If you think about it degrees C and K are in a scale of 0 - 100, so the kJ needed to bring 1 kg up by one degree K is the same amount of kJ to bring up 1 kg by one degree C

[@mhim9628]

If you graph temperature scales for Celsius and Kelvin you realize that one degree K is equivalent to one degree Celsius..not the same for Fahrenheit for example where 1.8F is around 1 C

[@adithyapop2390]

@least explain those terms in entropy balance equation mrf

[@川普-s9m]

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