10.1 Name TWO types of reaction turbines - NSC Mechanical Technology Fitting and Machining - Question 10 - 2018 - Paper 1
Question 10
10.1 Name TWO types of reaction turbines.
10.2 Explain the operation of the impulse turbine.
10.3 Why is it important to control the speed of a steam turbine?
10.... show full transcript
Worked Solution & Example Answer:10.1 Name TWO types of reaction turbines - NSC Mechanical Technology Fitting and Machining - Question 10 - 2018 - Paper 1
Step 1
10.1 Name TWO types of reaction turbines.
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Answer
Two types of reaction turbines are:
Francis turbine
Kaplan turbine
Step 2
10.2 Explain the operation of the impulse turbine.
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The impulse turbine operates by changing the velocity of a water jet. The jet acts on the turbine’s curved blades, altering the flow direction. As the water hits the blades, the change in momentum imparts a force on the blades, causing the turbine to spin. The turbine rotates without a pressure change at the blades, as the conversion of pressure to kinetic energy occurs through a nozzle before the water strikes the turbine.
Step 3
10.3 Why is it important to control the speed of a steam turbine?
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Controlling the speed of a steam turbine is crucial to prevent the rotor from reaching uncontrolled speeds, which can cause mechanical failure and pose safety risks.
Step 4
10.4 State THREE advantages of a gas turbine.
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Advantages of gas turbines include:
Smooth running due to the absence of reciprocating parts, leading to less friction and wear.
Quick starting capabilities.
Compatibility with a variety of fuels, allowing operational flexibility.
Step 5
10.5 What is the purpose of the waste gate in a turbocharger?
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The waste gate is designed to divert exhaust gases away from the turbine wheel, allowing the turbocharger to maintain optimal levels of boost pressure, thus preventing over-boost conditions.
Step 6
10.6 What effect does a high altitude have on the performance of the engine of a motor vehicle?
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At high altitudes, the engine performance may decrease due to reduced oxygen availability, which limits fuel combustion and results in lower power output.
Step 7
10.7 State ONE advantage of a turbocharger when compared to a supercharger.
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A key advantage of a turbocharger is its ability to utilize exhaust gases for power, enhancing engine efficiency while reducing the overall energy loss compared to a supercharger, which is mechanically driven.
Step 8
10.8 Identify the type of blower in FIGURE 10.8 used as a supercharger on an internal combustion engine.
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The blower depicted in FIGURE 10.8 is a Roots blower, commonly used as a supercharger in internal combustion engines.
