For Aspiring Aeronautical Engineer
First Law of Thermodynamics
The first law of thermodynamics states that the energy cannot be created nor destroyed it can only be changed from one form to another. Another name for this law is the law of conservation of energy. This means that the total energy of a system plus its surroundings is constant and does not change. Energy can, however, be transferred in or out of the system and to or from the surroundings through work or heat.
Conservation of Energy
Energy may be defined as the capacity to do work or to cause heat to flow. In the system term, energy may be defined as the property of a system that changes by an amount equal to the work or heat transferred across the system boundary. The total amount of energy that a system contains cannot be determined. We are accustomed therefore to measuring energy above some arbitrary datum. Energy is scalar quantity with no direction relative to the frame of reference. It can exist in different forms, in principle, all forms of energy are mutually convertible. There is a transfer or flow of energy when a change in form takes place.
First Corollary of the First Law The first corollary of the first law of thermodynamics is the application of the conservation of energy to a closed system. Final Energy – Initial Energy = Energy added to the system. E2 – E1 = Q + (-W) Where heat has been added (+Q) and work has been done to the system (-W) (PE2 + KE2 + U2) - (PE1 + KE1 + U1) = Q + (-W) The work described in the systems the work non-flow Q= PE + KE + U + WNF
Since additional mass is not allowed to enter and leave the system PE = Q= KE = 0,
U + WNF
∂Q = dU + ∂ WNF (Non-Flow Energy Equation)
Second Corollary of the First Law The second corollary of the first law of thermodynamics is the application of the conservation of energy to the open system.
E2 – E1 = Q + (-W) (PE2 + KE2 + U2 + Wf2) - (PE1 + KE1 + U1 + Wf1) = Q + (-W) the work describe in this system is the work steady flow (PE2 + KE2 + H2)
The first law of thermodynamics states that the energy cannot be created nor destroyed it can only be changed from one form to another. Another name for this law is the law of conservation of energy. This means that the total energy of a system plus its surroundings is constant and does not change. Energy can, however, be transferred in or out of the system and to or from the surroundings through work or heat.
Conservation of Energy
Energy may be defined as the capacity to do work or to cause heat to flow. In the system term, energy may be defined as the property of a system that changes by an amount equal to the work or heat transferred across the system boundary. The total amount of energy that a system contains cannot be determined. We are accustomed therefore to measuring energy above some arbitrary datum. Energy is scalar quantity with no direction relative to the frame of reference. It can exist in different forms, in principle, all forms of energy are mutually convertible. There is a transfer or flow of energy when a change in form takes place.
First Corollary of the First Law The first corollary of the first law of thermodynamics is the application of the conservation of energy to a closed system. Final Energy – Initial Energy = Energy added to the system. E2 – E1 = Q + (-W) Where heat has been added (+Q) and work has been done to the system (-W) (PE2 + KE2 + U2) - (PE1 + KE1 + U1) = Q + (-W) The work described in the systems the work non-flow Q= PE + KE + U + WNF
Since additional mass is not allowed to enter and leave the system PE = Q= KE = 0,
U + WNF
∂Q = dU + ∂ WNF (Non-Flow Energy Equation)
Second Corollary of the First Law The second corollary of the first law of thermodynamics is the application of the conservation of energy to the open system.
E2 – E1 = Q + (-W) (PE2 + KE2 + U2 + Wf2) - (PE1 + KE1 + U1 + Wf1) = Q + (-W) the work describe in this system is the work steady flow (PE2 + KE2 + H2)