Lab2.3.docx

University of Southern Philippines Foundation Salinas Drive, Lahug, Cebu Ciity College of Engineering and Architecture ME411 Lab2 Name: Jovito C. Delambaca Jr. Course: BSME-4

Experiment no. 3 Date:

TEST OF AN AIR COMPRESSOR (SINGLE STAGE RECIPROCATING) Title Theory The air we breathe has two major constituents. They are Nitrogen and Oxygen. The approximate composition of atmospheric air has 78% nitrogen, 21% oxygen and 1% other gases by volume and 76% nitrogen, 23% oxygen and 1% other gases by weight. Even though air is not a “perfect” gas, the presence of nitrogen and oxygen in major proportion makes it obey very closely to a “perfect” or “ideal” gas. We all know that an “Ideal” gas obeys some laws. They are 1. Boyle’s law (PV=C). 2. Charles’s law (V/T = C). The above two laws can be combined to form a combination law which can be represented as PV/T = C Objectives 1. To study all components/Accessories used in Reciprocating Air Compressor. 2. To investigate the effect of delivery pressure on the performance of reciprocating air compressor.

Apparatus SINGLE STAGE RECIPROCATING AIR COMPRESSOR TEST RIG

THERMACOUPLE

ENERGY METER U-GAUGE MANOMETER

Procedure: 1. The test rig consists of Air Compressor with an air suction tank, is fitted with an orifice at one end & other end connected to cylinder. 2. The orifice pressure tapping is connected to one limb of U -Tube manometer on panel. 3. Thermocouple T1, T2, T3 reads temperature at inlet ( T1 ) outlet Temperature ( T2 ) & ( T3 ) records temperature of air in receiver. 4. Energy meter is used to record the power input to motor & in turn the work required for compression. The control panel houses starter for motor, main switch, Temperature Indicator Findings As the volume of the space containing air reduces, the pressure increases. Also when volume V, is kept constant, the pressure P, is directly proportional to the temperature T. Thus as the pressure of the air is increased due to compressing, the temperature also increases. Thus as a result of compressing air, the pressure and temperature increases as the volume decreases. Observation Isothermal compression is compressing air with no change in temperature or at constant temperature. Adiabatic compression this process takes maximum energy input as no heat loss takes place through the cylinder walls. Conclusion The two theoretical compression processes, there are huge practical constraints to achieve. Thus the actual compression process is termed as polytropic compression. It is evident that the polytropic curve is in between both extremes i.e., adiabatic and isothermal compression curves.