Power Machines N6 — Document

December 2022 — N6 — Power Machines

N6 2022 Nated Engineering

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🎯 100 marks ⏱️ 3h 📄 5 pages 📝 38 items found

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Questions — A Preview of What to Expect in the Document

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Q1— Section header —

1.1In multistage compression, explain what is meant by perfect intercooling (2\

1.2In a single acting, two stage reciprocating compressor the delivery pressure is nine times the initial

1.2.1The absolute temperature before cooling and the absolute delivery temperature (4\

1.2.2The total power output n kilowatt (3\

1.2.3The swept volume of the low pressure cylinder in m (6\

1.2.4The volumetric efficiency, induced volume, and the swept volume of the high pressure cylinder in m (5\ [20]20

Q2— Section header —

2.1Explain the difference between actual dryness fraction and isentropic dryness fraction (3\

2.2Steam enters a convergent divergent nozzle dry saturated at a pressure of 900 kPa. At the throat,

2.2.1The specific enthalpy, the velocity in m/s and the specific volume of steam at the nozzle throat (8\

2.2.2The total actual exit enthalpy total exit isentropic enthalpy and

Q3— Section header —

3.1In a velocity compound impulse turbine, explain the purpose of the fixed row of blades (3\

3.2

3.2.1The fixed blade inlet angle (1\

3.2.2The first stage axial thrust in Newton (3\

3.2.3The turbine diagram efficiency (3\ [20]20

Q4— Section header —

4.1State the first law of thermodynamics in words. (3\

4.2

4.2.1The mass of steam generated in kilogram per kilogram of fuel burnt (4\

4.2.2The thermal efficiency of the whole plant (4\

4.2.3The energy absorbed by the evaporator, superheater and the air pre heater in kJ/kg of fuel (6\

4.2.4The percentage heat carried away with the flue gases at the chimney (3\ [20] 819004620

Q5— Section header —

5.1Explain the difference between indicated thermal efficiency and brake thermal efficiency of an engine. (3\

5.2A four cylinder, four stroke diesel engine has a bore and stroke length of 212 mm and 292 mm respectively. The engine 's brake

5.2.1ngine br ake power in kilowatt (4\

5.2.2uel mass flow rate per hour (3\

5.2.3rake thermal efficiency of the engine (3\

5.2.4olumetric efficiency of the engine (7\ [20]20

Q6— Section header —

6.1The compressor 's output isentropic and actual absolute temperature (4\

6.2The turbine 's output isentropic and actual absolute temperature (4\

6.3The compressor input power, the turbine output power and the plant net power output in kJ/min (5\

6.4The plant input thermal energy in kJ/s and the plant thermal efficiency (4\

6.5The plant work ratio. (3\ [20] TOTAL: 100 819004620

Mark Allocation

Total100 marks

Sections20 + 20 + 20 + 20 + 20 + 20 = 120 marks

Paper information

TitleDocument

SubjectPower Machines

LevelN6

Document typeQuestion paper

Year2022

MonthDecember

Pages11

Downloads5

Examination context

Decade2020s

Years ago4y

SeasonSummer (SH)

Start dayThursday

Exam periodDecember 2022

Days since exam1,412

About Power Machines examination preparation

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For stronger examination practice, complete the paper without unnecessary interruptions and keep track of the questions that take the most time. Afterwards, review the memorandum and separate knowledge gaps from mistakes caused by interpretation, calculation, structure, or examination technique.

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A practical revision approach

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File size239 KB

Pages11

Archived on8 September 2026

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