Nintendo Ds Good For Toddler

Thermodynamic efficiency

This course has enabled it to address the thermodynamic efficiency clacul initially for one cycle, then for an open system.

In the case of the cycle, we show that the maximum yield can be given by the Carnot formula:

yield = 1 - Tf / Tc

For an open system, the device is compared to an ideal device as well Nature:

• for a turbine, it takes a turbine adiabatic reversible (isentropic) operating between the same state at the entrance and the same pressure at the exhaust;
• for a compressor, it takes either a compressor adiabatic reversible ( isentropic) isothermal compressor is reversible in both cases, they operate between the same state at the entrance and the same pressure in the exhaust.

Corporate Bond Yahoo Historical

The second law of thermodynamics

This course introduces the concept of entropy. This new state function allows to know the meaning of evolution and is therefore linked to the notion of irreversibility.

The second principle states:
"Increasing'entropie of an isolated system can only be positive or zero."

The course has helped to establish the equation for calculating the vairiation entropy of a system open. This entropy change is related to heat exchange with the external environment on the one hand, and mass exchanges (input, output).

In the general case, we can not consider that the wall temperature of the system is uniform. We must therefore divide the heat exchanged in small areas isotherms.

To use this equation, we use two assumptions:

• Evolution with steady-state flow: this hypothesis in the case of a reversible adiabatic evolution for a sustem having an input and an output, led to an evolution isentropic ;
• Evolution with uniform flow.