# Reply To: Thermal & Fluid Mechanics Queries…

All About Education Forums Mechanical Engineering Thermal & Fluid Mechanics Queries… Reply To: Thermal & Fluid Mechanics Queries…

1. @Ritesh: Absolutely it is always be zero. Work = Integration of P*dV. Now as Volume is constant it means change in volume is zero i.e. dV is zero, which results in zero work done.
Lets took it in this way. Consider the standard “Piston-Cylinder” example. Whatever u do in the system (either change pressure or Temp.) but its volume is going to be same as it is Constant Volume process. So if u remember the definition of “Work” ; it is Force*Displacement. So it requires “Displacement”
In this process there is no displacement of the piston because it will change the Volume of the cylinder so it will violet our essential requirement of “Constant Volume”. And also as it is “Closed System” no mass can cross the boundary of system so that there is no chance of Work to be done on the mass so it could cross the boundary.
So moral of the story is “For a Closed System Constant Volume process work done will ALWAYS be zero”