Homework: Constant Volume Heat Addition & Removal


The first law of thermodynamics establishes a balance between the internal energy, heat transfer to/from, and work done on/by a system. It is essentially the law of conservation of energy and can be written in the form shown below. In a system where there is no change in volume (constant volume system) and consequently, there is no work done on/by the system, the change in internal energy is directly dependent on the heat transfer to/from the system. This change in internal energy causes a change in the temperature of the fluid. In this example, we will look at one such case where air is heated and cooled inside a closed adiabatic container.


In the homework, you will simulate a closed constant volume thermodynamic system in which heat is added and removed through a volumetric source inside the system. You will learn how to set up the simulation in Ansys Fluent, including adding energy sources to the model, and understand the working of the first law of thermodynamics.


Download the Mesh file needed for setting up the simulation and the associated Case & Data files here. Follow the instructions below to set up this simulation in Ansys Fluent starting with the Mesh file. In case you face any issues setting up or running the simulation, refer to the corresponding initial and final Case and Data files.

Alternate video link.

Results and Discussion

Let's take a look at some results and understand how the first law of thermodynamics is enforced in this closed system.