Lesson 9 COMPRESSION PROCESSES Apply the ideal gas laws to SOLVE for the unknown pressure, temperature, or volume. DESCRIBE when a fluid may be considered to be incompressible. CALCULATE the work done in constant pressure and constant volume processes. DESCRIBE the effects of pressure changes on confined fluids. DESCRIBE the effects of temperature changes on confined fluids.

Boyle’s Law The pressure of a gas expanding at constant temperature varies inversely to the volume or (P 1 )(V 1 ) = (P 2 )(V 2 ) = (P 3 )(V 3 ) = constant.

Charles’ Law The pressure of a gas varies directly with temperature when the volume is held constant, and the volume varies directly with temperature when the pressure is held constant or V 1 /V 2 = T 1 /T 2 or P 1 /P 2 = T 1 /T 2

Ideal Gas Law Combination of Charles' and Boyle's Laws gives P v /T = constant This is the ideal gas constant and is designated by R The ideal gas equation becomes Pv = RT where the pressure and temperature are absolute values.

Ideal Gas Constant Values

Pressure – Volume Diagram

Fluids Any substance that conforms to the shape of its container. It may be either a liquid or a gas. Compressibility – Liquid – Incompressible – Gas – Compressible Constant Pressure Process – W 1-2 = P(ΔV) Constant Volume Process – W 1-2 = V(ΔP) – W 1-2 = mv(ΔP) Effects of Pressure and Temperature changes on Fluid Properties

Air Compressors Types Classifications Components Principles of Operation Failure Mechanisms and Symptoms

Air Compressors - Types Rotary Reciprocating Centrifugal

Air Compressors - Classifications Pressure Construction and Operation Features Air Quality

Air Compressors – Classifications Pressure Low-pressure air compressors (LPACs) - discharge pressure of 150 psi or less Medium-pressure compressors - discharge pressure of 151 psi to 1,000 psi High-pressure air compressors (HPACs) - discharge pressure above 1,000 psi

Air Compressors – Classifications Construction and Operation Features Positive Displacement Type – Reciprocating – Rotary Rotary Screw Rotary Vane Dynamic Type. – Centrifugal – Axial Flow – Blower Article Source:

Air Compressors - Components Staging Relief valve Cooling water

Air Compressors – Principles of Operation Two primary components – Compressing mechanism - helps in compressing atmospheric air by using energy from the power source. piston, rotating impeller vane – Power source. – electric motor – other energy sources. Atmospheric air is drawn in through an intake valve More and more air is pulled inside a limited space mechanically by means of the compressing mechanism Amount of air is increased in the constant volume receiver or storage tank, pressure is raised automatically. When pressure increases to the maximum pressure setting in the receiver or tank, the pressure switch shuts off the intake of air in the compressor. When the compressed air is used, the pressure level falls. As the pressure drops to a low pressure setting, the pressure switch is turned on, thus allowing the intake of atmospheric air. Cycle continues

Air Compressor Failure Mechanisms and Symptoms Power loss Line ruptures Air pressure reduction Air operated component repositioning

Diesel Engines Principles of Operation Main Structural Components Main Moving Components Accessories/ Support Systems Failure Mechanisms and Symptoms

Diesel Engine Principles of Operation Internal Combustion Compression ignition Diesel Cycle

Idealized Diesel Cycle

Diesel Engine Main Structural Components Frame Block Pedestal Fuel distribution system

Diesel Engine Main Moving Components Pistons Cylinders Crankshaft Bearings Valves Control air Turbochargers

Diesel Engine Accessories/ Support Systems Air start Cooling water Lube oil Electrical Fuel oil distribution

Diesel Engine Failure Mechanisms and Symptoms Failure to start Failure to reach operating speed Failure to stop Rough idling