MARL015
Apply intermediate principles of marine engineering thermodynamics


Application

This unit involves the skills and knowledge required to apply intermediate principles of marine engineering thermodynamics to perform calculations and explain the operation of marine machinery, including engines, compressors, steam plants, refrigeration and air-conditioning units.

This unit applies to the work of a Marine Engineer Class 2 on commercial vessels greater than 3000 kW and forms part of the requirements for the Certificate of Competency Marine Engineer Class 2 issued by the Australian Maritime Safety Authority (AMSA).

No licensing, legislative or certification requirements apply to this unit at the time of publication.


Elements and Performance Criteria

Elements describe the essential outcomes.

Performance criteria describe the performance needed to demonstrate achievement of the element.

1

Calculate heat mixtures involving water equivalent, change of phase, and feed heating

1.1

Key terms associated with heat transmission are explained

1.2

Heat transfer is calculated between liquids and solids using water equivalent

1.3

Flow is differentiated from non-flow heating and cooling processes

1.4

Effects of superheating and sub-cooling on steam plant efficiency are outlined

1.5

Mass balance throughout a steam plant cycle is constructed and effects of pressure and temperature on cycle efficiency are analysed

2

Determine fluid properties of steam

2.1

Relationship between saturated and superheated steam, including dryness fraction, is explained

2.2

Regions on a temperature/enthalpy diagram are constructed and identified

2.3

Steam tables are used to determine fluid properties

2.4

Changes of enthalpy throughout a system are identified

2.5

Operating principles and application in steam plants of throttling, separating and combined throttling, and separating calorimeters are explained

2.6

Calorimeters are applied to determine dryness fraction of steam

3

Calculate boiler efficiency and boiler water density

3.1

Efficiency of saturated and superheated steam boilers is calculated

3.2

Where loss of efficiency occurs is shown

3.3

Concept of parts per million for density of boiler water is explained

3.4

Changes in boiler water density due to contaminated feed are calculated

3.5

How acceptable dissolved solids and water levels may be maintained in a boiler is shown

4

Determine steam turbine velocity

4.1

Principles and differences between pressure and velocity changes in reaction and impulse steam turbines are explained

4.2

Velocity diagrams to calculate steam velocity at exit of nozzles and blades are applied

4.3

Graphical and mathematical methods to determine blade angle, steam velocity, thrust, power, and efficiency of single stage impulse and reaction steam turbines are applied

5

Calculate calorific value and the air fuel ratio for solid and liquid fuels

5.1

Elements and compounds present in fuel and the products of combustion are evaluated

5.2

Air/fuel ratio, gravimetric and volumetric analysis are explained

5.3

Chemical equations for combustion elements and compounds are developed and elements of combustion are analysed

5.4

Bomb calorimeter is used to find calorific value of a fuel

5.5

Formula to calculate calorific value of a fuel from mass analysis of fuel is applied

5.6

Air required for combustion is calculated

6

Calculate thermal expansion

6.1

Coefficient of linear expansion and its significance to different materials is explained

6.2

Clearances and shrunk fit allowances are calculated

6.3

Stresses generated with restricted expansion are calculated

6.4

Volumetric expansion of solid and liquids, and allowance required for fluid expansion in tanks and systems is calculated

7

Apply gas law equations

7.1

Compression and pressure ratio is explained and related to combined gas law equation

7.2

Combined gas law equation is applied to constant volume and constant pressure processes

7.3

Specific gas constant of a gas or mixture of gases is calculated

7.4

Differentiation is made between specific heat of gases, ratio of specific heats, work and change in internal energy

7.5

Changes in internal energy associated with specific heat of gases, ratio of specific heats and work are calculated

8

Calculate gas conditions, work and thermal efficiency of internal combustion engines

8.1

Processes associated with expansion and compression of gases are explained

8.2

Gas conditions and index of compression at end of each process are determined

8.3

Work formula is derived for each process and derived formula is applied to calculate work and power per cycle

8.4

Air standard cycle is applied to determine amount of fuel consumed and work produced by an internal combustion engine

8.5

Differentiation is made between air standard efficiency and thermal efficiency

8.6

Thermal efficiency of engine cycles is calculated

9

Perform calculations related to refrigeration and air conditioning cycles

9.1

Pressure/enthalpy diagram is applied to describe the refrigeration cycle

9.2

Importance of superheating and under-cooling in determining stability and well-functioning of refrigeration systems is explained

9.3

Properties and hazards of refrigerants used in refrigeration and air conditioning systems are identified

9.4

Refrigeration tables are applied to calculate refrigeration effect, cooling load and coefficient of performance

9.5

Basic air conditioning cycles are explained

9.6

Wet and dry bulb temperatures are explained

9.7

Humidity conditions are determined using psychrometric charts

10

Solve heat transfer problems involving flat plates and thin cylinders

10.1

Different forms of heat transfer are identified

10.2

Heat flow through composite flat plates using thermal conductivity is calculated

10.3

Interface temperatures of composite flat layers are calculated

10.4

Radial conduction of heat through a thin cylinder is calculated

11

Solve problems related to single and multi stage air compression

11.1

Pressure–volume diagram is applied to describe operating cycle of reciprocating compressors

11.2

Work done by constant pressure, isothermal processes and polytropic processes in reciprocating compressors is calculated

11.3

Effect of clearance volume on efficiency of reciprocating compressors is explained

11.4

Volumetric efficiency and free air discharge in reciprocating compressors is calculated

11.5

Volume, mass flow and temperature are calculated at completion of each process in reciprocating compressors

11.6

How inter-cooling and after-cooling affects overall efficiency of reciprocating compressors is explained

11.7

Quantity of cooling water required by reciprocating compressors is calculated

12

Perform calculations related to engine power and heat balances

12.1

Indicator and timing diagrams for internal combustion engines are plotted

12.2

Formula is applied to solve problems related to indicated power of internal combustion engines

12.3

Formula is applied to solve problems related to brake power of internal combustion engines

12.4

Morse test is applied to determine the indicated power of internal combustion engines

12.5

Tabular and graphical heat balance diagrams are applied to calculate mechanical, thermal and overall efficiencies of internal combustion engines

Evidence of Performance

Evidence required to demonstrate competence in this unit must be relevant to and satisfy all of the requirements of the elements, performance criteria and range of conditions on at least one occasion and include:

applying relevant work health and safety/occupational health and safety (WHS/OHS) requirements and work practices

assessing own work outcomes and maintaining knowledge of current codes, standards, regulations and industry practices

effectively communicating knowledge and ideas through verbal, written and visual means

identifying and applying appropriate laws and principles and relevant mathematical formulas and techniques to solve basic problems related to marine engineering thermodynamics

identifying and interpreting numerical and graphical information, and performing basic mathematical calculations related to marine engineering thermodynamics, such as gas expansion and contraction, heat transfer, and thermal efficiency

identifying, collating and processing information required to perform basic calculations related to marine engineering thermodynamics

reading and interpreting written information needed to perform basic calculations related to marine engineering thermodynamics.


Evidence of Knowledge

Evidence required to demonstrate competence in this unit must be relevant to and satisfy all of the requirements of the elements, performance criteria and range of conditions and include knowledge of:

air compressor:

components

faults and hazards

first law of thermodynamics

operating cycle of reciprocating air compressors

performance characteristics

property diagrams

types

uses

working principles of reciprocating compressors

basic principles of marine engineering thermodynamics

enthalpy

expansion and compression of gases

gas laws

internal combustion engines:

second law of thermodynamics

heat engine cycles

operating principles of two stroke and four stroke internal combustion engines

performance characteristics

improvements

principles of heat transfer and refrigeration

refrigeration and air conditioning cycles

steam plants

System International (SI) units

thermal efficiency calculations

thermodynamic principles

WHS/OHS requirements and work practices


Assessment Conditions

Assessors must satisfy National Vocational Education and Training Regulator (NVR)/Australian Quality Training Framework (AQTF) assessor requirements.

Assessment must satisfy the National Vocational Education and Training Regulator (NVR)/Australian Quality Training Framework (AQTF) standards.

Assessment processes and techniques must be appropriate to the language, literacy and numeracy requirements of the work being performed and the needs of the candidate.

Assessment must occur in workplace operational situations or where these are not available, in simulated workplace operational situations or an industry-approved marine operations site that replicates workplace conditions where intermediate principles of marine engineering thermodynamics can be applied.

Resources for assessment include access to:

applicable documentation including workplace procedures, regulations, codes of practice and operation manuals

diagrams, specifications and other information required for performing intermediate calculations related to marine engineering thermodynamics

relevant and appropriate materials and equipment

relevant regulatory and equipment documentation that impacts on work activities

technical reference library with current publications on intermediate marine thermodynamics.

Performance should be demonstrated consistently over time and in a suitable range of contexts.


Foundation Skills

Foundation skills essential to performance are explicit in the performance criteria of this unit of competency.


Range Statement

Range is restricted to essential operating conditions and any other variables essential to the work environment.

Key terms include:

enthalpy of fusion

evaporation

sensible heat

transfer of heat energy

Processes include one or more of the following:

adiabatic

isothermal

polytropic

Fluid properties include one or more of the following:

density

dryness faction

enthalpy of water

pressure

saturated steam

specific volume

superheated steam

temperature

Forms of heat transfer must include:

conduction

convection

radiation


Sectors

Not applicable.


Competency Field

L – Marine Engineering