Conservation of Energy to Fluid Mechanics

Conservation of Energy

          The first law of thermodynamics can be formulated as the principle of conservation of energy2:

          where Ein represents all types of energy added to the system within a defined control boundary during a specified time interval, Es is the change in the total energy of the system, and Eout represents all kinds of energy substracted from the system in the same time interval. In the steady-flow system Es 0, and

            With fluid flow through the system, the energy entering (or leaving) this system by a duct (or a pipeline) will consist of potential (external), kinetic, and internal energy of the fluid, and also the external pumping work, the energy transmitted by a pump to force the fluid to flow continuously across the boundary of the system. Then the total rate of steady-flow energy transported in a duct (or a pipe) is:

where J 778.169 (ft lbf)/Btu (dimensional conversion factor).