Home » Mechanical Engineering » Compressors, Gas Dynamics and Gas Turbines

Purpose of intercooling in multi-stage air compressors: choose the primary objective. Select the main reason intercoolers are used between compression stages.

Difficulty: Easy

To cool the air during compression
To cool the air at delivery
To enable compression in two stages
To minimise the work of compression

Correct Answer: To minimise the work of compression

Explanation:

Concept/Approach
For a given overall pressure ratio, the compression work W ∝ ∫ v dp. Reducing the specific volume by cooling between stages lowers the required work.

Key result
Perfect intercooling (returning to the initial temperature) with equal pressure ratios per stage minimizes total work.

Final Answer
To minimise the work of compression.

← Previous Question Next Question→

More Questions from Compressors, Gas Dynamics and Gas Turbines

Where does stagnation pressure rise occur in a centrifugal compressor? Identify the component(s) responsible for the increase in total (stagnation) pressure.
Rotary compressors used in aircraft: select the common type for high-throughput, high-speed applications. Choose the type of rotary compressor predominantly used in aeroplanes.
Effect of speed on centrifugal compressor performance at a given pressure ratio: choose the correct trend. For a centrifugal compressor operating at a fixed pressure ratio, what is the typical effect of increasing rotational speed?
Heat rejection accounting in a multi-stage reciprocating air compressor with intercooling. Validate the energy balance statement: The total heat rejected equals (heat rejected during polytropic compression per kg of air) + (heat rejected in the intercooler per kg of air). Choose whether the statement is correct.
Gas turbines: effect of a high air–fuel ratio on performance and temperatures Consider a gas turbine operating with a high (lean) air–fuel ratio relative to stoichiometric conditions. Choose the correct outcome that most directly follows from this condition.
Two-stage reciprocating air compressor with complete intercooling: diameter ratio relation Let p₁ be the suction pressure to the L.P. cylinder and p₂ the pressure leaving the L.P. cylinder (intercooler pressure). For a single-acting, two-stage reciprocating air compressor with complete intercooling, what is the correct relation for the cylinder diameter ratio D₁/D₂? Choose the correct option.
Four-stage compressor with equal pressure ratio per stage: determine fourth-stage delivery pressure In a four-stage compressor operating with equal pressure ratio per stage, the pressures at the first and third stage are given as 1 bar and 16 bar, respectively. Assuming standard textbook staging with equal ratios, compute the delivery pressure at the fourth stage and choose the closest option.
Axial-flow compressor aerodynamics: exit flow deviation dependence In an axial-flow compressor, the deviation of the exit flow angle from the blade angle primarily depends on which geometric/flow parameters? Choose the correct option.
Single-acting reciprocating compressor: strokes for suction, compression, and delivery In a single-acting reciprocating air compressor, over how many piston strokes do suction, compression, and delivery occur? Choose the correct option.
Effect of clearance volume on compression work per kg in reciprocating compressors In a reciprocating air compressor, how does the compression work per kilogram of air vary with clearance volume (other conditions fixed)? Choose the correct option.

Discussion & Comments

No comments yet. Be the first to comment!

Join Discussion