4.1 Thermodynamic Analysis of Control Volumes

The total energy of a flowing fluid of mass δm is θδm. Then the total energy transported by mass throughan inlet or exit (Θ i , Θ e) is obtained by integrating. At an inlet, for example, it becomes ...or, in the rate form ...(4.4.5)(4.4.6)The energy equation for unsteady-processes in control volumes becomes:(4.4.7)... and ...(4.4.8)Uniform-Flow Processes:A uniform-flow process is a simplified unsteady-flow process involving the following idealizations:‚ At any instant during the process, the state of the control volume is uniform (the samethroughout spatially). Therefore, the state of the mass exiting the control volume at any instant is thesame as the state of the mass in the control volume at that instant.‚ The fluid properties may differ from one inlet or exit to another, but the fluid flow at an inlet orexit is uniform and steady.Under these idealizations, Eq. (4.4.7) becomes ...(4.4.9)where u 1 and u 2 are the initial and final specific internal energies of the system.ENGS205--Introductory Thermodynamics page 39