Experiment Report

Topics: Thermodynamics, Temperature, Pressure Pages: 3 (840 words) Published: February 27, 2013
EXPERIMENT 3: ISENTROPIC EXPANSION PROCESS
Objective
In order to demonstrate the isentropic expansion process.
Introduction
Isentropic means no change in entropy. Entropy is a thermodynamic property that is the measure of a system’s thermal energy per unit temperature that is unavailable for doing useful work. In simple terms, the measure of the level of disorder in a closed but changing system, a system in which energy can only be transferred in one direction from an ordered state to a disordered state. Higher the entropy, higher the disorder and lower the availability of the system's energy to do useful work.

The expansion process which assumes there is no heat transfer between the system and its surroundings. No heat transfer is called "adiabatic. A isentropic process is for purposes of engineering analysis and calculation, one may assume that the process takes place from initiation to completion without an increase or decrease in the entropy of the system. An isentropic process is an idealisation Since the isentropic process is adiabatic which no heat transfer, therefore the isentropic process is S1 = S2. In mathematically, the equation for isentropic perfect gas is derived as following: T2T1 = ( P2P1 )k-1k

Where,
P1 and T1 is initial absolute Temperature and absolute Pressure P2 and T2 is Temperature and Pressure after the expansion.
Materials and Apparatus:
Perfect gas expansion unit
Procedure
1. General start up procedure is performed as stated in appendix A. All valve are fully closed 2. The hose is connected from compressive pump to pressurized chamber 3. The compressive pump is switched on and the pressure inside chamber is allowed to increase up to 160kPa.The pump is switched off and the hose is removed from the chamber 4. The pressure reading inside the chamber is monitored until stabilized. The pressure reading P1 and temperature T1 is recorded. 5. Valve V01 is slightly opened and the air is allowed to flow out slowly...

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