Technical University “Gheorghe Asachi” of Iaşi
Mechanical Engineering Faculty
Department of Thermotechnics, Thermal Machines, Refrigeration and Air Conditioning
Year: 2006 / 2007
CURRICULA for
COMPRESSORS
Category of discipline:
-Technical Discipline (TD),
-Compulsory Discipline (CD)
Discipline titular: Lecturer HOMUTESCU VLAD MARIO, PhD.
Structure of the discipline:
Semester
/ Nr. of hours / week / Evaluation / Total hours / Whole disciplineC / S / L / P / C / S / L / P
7 / 3 / 1 / Exam. / 42 / 14 / 56
A. COURSE
1. Introduction2 hours
Definitions. Compressor as a generator machine. Ways to increase pressure. Compressors classifications and applications. Principal functional parameters. Example of a compressor installation
2. Volumetric (positive) displacement compressors. Introduction. Internal and external compression
2.1. Reciprocating compressors15 hours
2.1.1. Construction of single-stage reciprocating compressor. Components. Motive drive. Valves
2.1.2. Thermodynamic processes inside reciprocating compressors
2.1.2.1. Theoretical thermodynamic cycle of the single-stage reciprocating compressor. Hypotheses. Functional processes. Thermodynamic cycle representation in p-V and T-S diagrams
2.1.2.2. Energies exchanged with the exterior by the theoretical reciprocating compressor. Work and heat exchanged
2.1.2.3. Theoretical capacity (flow rate). Isothermal efficiency, specific energy consumption
2.1.2.4. Theoretical multistage reciprocating compressor. Performing the compression in more than one stage. Representation of the processes inside a two-stage reciprocating compressor in p-V and T-S diagrams
2.1.2.5. Stage optimal compression ratio. Generalizing the relation obtained for the two-stage compressor at the z-stage compressor. Correlation between stage swept volumes
2.1.2.6. Heat exchanged in multistage reciprocating compressors. Isothermal efficiency. Theoretical multistage reciprocating compressor behavior at the discharging pressure variations
2.1.2.7. Real stage process. Influence factors. Clearance volume, maximum theoretical compression ratio. Suction and discharging pressure. Heat exchanged between gas and cylinder walls. Processes representation in p-V and T-S diagram
2.1.2.8. Volumetric capacity of the reciprocating compressor. Capacity coefficient
2.1.2.9. Energy consumption in the real compressor determined based on the indicator diagram. Simplifying hypotheses. Efficiencies (isothermal, adiabatic, mechanical, brake horsepower)
2.1.2.10. The real multistage compression. Particularities, processes representation in p-V and T-S diagrams, optimal compression ratio for the intermediate stages
2.1.2.11. Factors that influence the isothermal efficiency
2.1.2.12. Reciprocating compressor characteristic curves. Pressure and speed characteristic
2.2. Rotary compressors (with motion in a circular path). Classification4 hours
2.2.1. Sliding-vane compressor construction and functioning. Working with different discharging pressure
2.2.2. Construction and functioning of the compressor with sliding-vane in stator. Functional volumes. Volume variation laws
2.2.3. Liquid ring vacuum compressor (pump). Construction and functioning
2.2.4. Roots and Aerzener compressors
2.2.5. Twin-rotor screw-type compressor (Lysholm). Construction and functioning
3. Dynamic compressors
3.1. Centrifugal compressors9 hours
3.1.1. Single-stage centrifugal compressor construction and functioning
3.1.2. Representation of the compression process in T-S, p-V, p-x and i-x diagrams
3.1.3. Thermodynamic process in the rotor zone. Obtaining the expression of the absolute pressure increasing with the help of the momentum equation. The pressure increasing expression function of the absolute velocity components. The specific work of the centrifugal force
3.1.4. Processes inside the centrifugal compressor inlet stationary blades zone. Rotor constructive variants. Influence of angle β2p over the increasing of the absolute pressure in the rotor zone
3.1.5. Kinematic percentage of reaction. Definitions
3.1.6. The rotor with finite number of blades. Forces equilibrium. Differential equations for the flow inside the centrifugal rotor
3.2. Axial compressors9 hours
3.2.1. Construction of a stationary axial compressor and of an axial compressor for a gas-turbine engine
3.2.2. Axial stage kinematics
3.2.3. Thermodynamic aspects of the gas flowing inside the axial compressor. Efficiencies, power, specific work. The expression of specific work in function of absolute speed components
3.2.4. Thermodynamic isentropic percentage of reaction. Kinematic percentage of reaction. Expressions
3.2.5. Elementary axial stage types, with different percentage of reaction. Comparison between elementary axial stage types for Mw1 = ct. and for u = ct.
3.2.6. Characteristic curves for dynamic compressors: Capacity curves, speed curves. Universal characteristics
4. Compressors constructive and functional elements3 hours
4.1. Gas distribution wits independent valves. Valve placing. Constructive solutions for compressor valves
4.2. Regulating and automating the compressors functioning. Positive displacement compressors regulation. Dynamic compressors regulation
4.3. Equipment for lubrication and cooling. Lubrication system of a reciprocating compressor. Compressor cooling systems
4.4. Auxiliary equipment and compressor plant layout: driving engines; foundation and casing; manifolds; piping; filters; purger; water and oil separator; receiver (air bottle); instrumentation; devices for protection and warding; automation devices
B. APPLICATIONS
Laboratory themes:
1. Disassembling and assembling of various positive displacement and dynamic compressor types (2 hours)
2. Disassembling and assembling of various valves(2 hours)
3. Pressure and speed characteristic curves for a single-stage reciprocating compressor(2 hours)
4. Pressure and speed characteristic curves for a two-stage reciprocating compressor(2 hours)
5. Measuring the capacity for a volumetric displacement compressor(2 hours)
6. Thermodynamic synthesis of the gas flow for an axial compressor stage(2 hours)
7. Thermodynamic synthesis of the gas flow for a centrifugal compressor stage(2 hours)
References
1. Giurcă, V.,Compressors. Vol. I. Reciprocating Compressors. Rotaprint, I.P.I., 1993 (in Romanian).
2. Giurcă, V.,Compressors. Vol. II. Positive Displacement Compressors. Dynamic Compressors. Rotaprint, I.P.I., 1985 (in Romanian).
3. Giurcă, V., Zubcu Dorina Silvia, Compressors. Laboratory manual. Rotaprint, I.P.I., 1984 (in Romanian).
4. Homutescu V.M., Homutescu C.A., Homutescu A., Thermal and Hydraulic Machines and Installations. Cermi Publishing House, Iaşi, 2001 (in Romanian).
5. Pimsner, V., Blade Machines. Tehnica Publishing House, Bucharest, 1988 (in Romanian).
6. Pimsner, V.,Processes in Thermal Machines with Blades. Applications and Problems. Tehnica Publishing House, Bucharest, 1986 (in Romanian).
Lect.dr.eng. Vlad Mario HOMUTESCU
Dean,
Prof. dr. eng. Spiridon CRETU