We have seen the basic concepts and also method of
calculations of heat energy transfer and work energy transfer in the field of
thermal engineering. We have also mentioned in our previous post to see the
basic concepts for each type of work transfer in the field of thermal
engineering and so we have already seen the “Displacement work or PdV work inthermodynamics”.
Today we will see here another type of work transfer i.e. Paddle wheel work in the field of thermal engineering.
Paddle wheel work or stirrer work
Let we have one container with liquid as displayed
here in figure. We can see here the stirrer or paddle wheel which will be
rotated mechanically. In order to rotate the stirrer or paddle wheel, we will
have to go for lowering the weight as displayed here.
Now we will have one question in our mind, what we want to explain here?
Liquid in container will be considered as the system
here and let us assume that initially system is at state 1. As we are observing
here that work is being transferred here from surrounding to the system.
Therefore we can say that work is done on the system from the surrounding and hence system will be now at another state say it state 2 due to this work energy transfer.
Therefore we can say that work is done on the system from the surrounding and hence system will be now at another state say it state 2 due to this work energy transfer.
Temperature of liquid in container will be increased,
when stirrer or paddle wheel will be rotated. We must note it here that some
other thermodynamic properties might also be changed due to changing in
temperature of the system depending on the relationship of respective thermodynamic
property with temperature.
We will see flow work transfer and shaft work transfer
in our next post in thermodynamics.
Do you have suggestions? Please write in comment
box.
Reference:
Engineering thermodynamics by P. K. nag
Engineering thermodynamics by r. k. Rajput
Image courtesy: Google
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