Unit 43 Plant and Process Principles


Unit 43:

Plant and Process Principles


Unit code:
H/601/1442

QCF level:
5


Credit value:
15






Aim

This unit will develop learners’ understanding of some of the engineering principles that underpin the design and operation of plant engineering systems and equipment.

Unit abstract

It is envisaged that the content of this unit will be used as part of an integrated programme of plant engineering services and management, with the services aspect being applications orientated and developed through knowledge of thermofluid principles.

Learning outcome 1 will introduce learners to the concept of thermodynamic systems and their properties. This lays the foundation for the future study of heat engines. Learning outcome 2 seeks to provide learners with knowledge of common mechanical power transmission system elements. Learning outcome 3 will provide the learner with knowledge of static and dynamic fluid systems. This will lay the foundation for future study of fluid mechanics. In the final learning outcome, learners will investigate combustion processes, the associated chemistry and analysis of the products of combustion.

Learning outcomes

On successful completion of this unit a learner will:

1      Understand thermodynamic systems as applied to plant engineering processes

2    Understand power transmission system elements in relation to plant engineering equipment

3    Understand static and dynamic fluid systems with reference to plant engineering

4      Understand combustion processes associated with plant engineering.




Unit content

1      Understand thermodynamic systems as applied to plant engineering processes

Thermodynamic systems: closed systems; open systems; application of 1st Law to derive system energy equations; enthalpy

Properties: system properties eg intensive, extensive, two-property rule

Polytropic processes: general equation pvn = c; relationships between index ‘n’ and heat transfer during a process; constant pressure and reversible isothermal and adiabatic processes; expressions for work flow

Relationships: system constants for a perfect gas eg R = cp - cv and γ = cp/cv


2      Understand power transmission system elements in relation to plant engineering equipment

Belt drives: flat and vee-section belts; limiting coefficient friction; limiting slack and tight side tensions; initial tension requirements; maximum power transmitted

Friction clutches: flat, single and multi-plate clutches; conical clutches; coefficient of friction; spring force requirements; maximum power transmitted by constant wear and constant pressure theories; validity of theories

Gear trains: simple, compound and epicyclic gear trains; determination of velocity ratios; torque, speed and power relationships; efficiency; fixing torques

3      Understand static and dynamic fluid systems with reference to plant engineering

Immersed surfaces: rectangular and circular surfaces, including retaining walls, tank sides, sluice gates, inspection covers, valve flanges; hydrostatic pressure and thrust on immersed surfaces

Centre of pressure: use of parallel axis theorem for immersed rectangular and circular surfaces

Viscosity: shear stress; shear rate; dynamic viscosity; kinematic viscosity

Pipeline flow: head losses eg Bernoulli’s equation and determination of head loss in pipes by D’Arcy’s formula; Moody diagram; head loss due to sudden enlargement and contraction of pipe diameter; head loss at entrance to a pipe; head loss in valves; Reynolds’ number; inertia and viscous resistance forces; laminar and turbulent flow; critical velocities

Impact of a jet: power of a jet; normal thrust on a moving flat vane; thrust on a moving hemispherical cup; velocity diagrams to determine thrust on moving curved vanes; fluid friction losses; system efficiency

4      Understand combustion processes associated with plant engineering.

Combustion chemistry: composition of air and simple hydrocarbon fuels; combustion equations; stoichiometric and actual air:fuel ratios; mixture strength; excess air

Energy of combustion: calorific values; higher and lower; thermal and boiler efficiency; practical determination of calorific value of various solid, liquid and gaseous fuels

Products of combustion: instrumentation for flue gas and exhaust products; volumetric analysis; variation of proportions of products dependent on air:fuel ratio and combustion quality



Learning outcomes and assessment criteria




Learning outcomes
Assessment criteria for pass


On successful completion of
The learner can:


this unit a learner will:










LO1 Understand thermodynamic

1.1
discuss thermodynamic systems and their properties


systems as applied to plant

1.2
examine the application of the 1st law of


engineering processes





thermodynamics to thermodynamic systems









1.3
evaluate polytropic processes




1.4
determine the relationships between system constants





for a perfect gas








LO2 Understand power

2.1
determine the maximum power which can be


transmission system


transmitted by means of a belt and by a friction clutch


elements in relation to plant

2.2
determine the torque and power transmitted through


engineering equipment





gear trains












LO3 Understand static and

3.1
determine the hydrostatic pressure and thrust on


dynamic fluid systems with


immersed surfaces


reference to plant

3.2
determine the centre of pressure on immersed surfaces


engineering










3.3
explain viscosity in fluids




3.4
determine fluid flow in a pipeline




3.5
assess the impact of a jet of fluid







LO4 Understand combustion

4.1
explain the combustion process using terminology


processes associated with


associated with combustion chemistry


plant engineering

4.2
determine energy of combustion








4.3
explain how products of combustion are formed.









Guidance

Links

This unit can be linked with Unit 1: Analytical Methods for Engineers and Unit 2: Engineering Science. It can also support the delivery of Unit 41: Fluid Mechanics and Unit 61: Engineering Thermodynamics.

Essential requirements

Centres will need to provide access to laboratory facilities for the investigation of fluid flow and a hydraulics bench with attachments for the investigation of pipeline flow and the impact of a jet of fluid. Facilities will also need to be available for the investigation of combustion processes and the calorimetric properties of gases and fuels.

Employer engagement and vocational contexts

Liaison with plant engineering and process companies would be useful in giving learners the opportunity to witness the operation of plant engineering systems and equipment at first hand.

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