GATE AE 2007 • Q63 MCQ • 2 Marks Propulsion

Propulsion

Compressors and Turbines

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

Question Statement:

If the polytropic efficiency of the compressor is 0.89, then the isentropic efficiency of the compressor is

Options:

  • (A) 0.613
  • (B) 0.869
  • (C) 0.89
  • (D) 0.98

Official Answer Key:

B

Step-by-Step Solution & Explanation

### **Dedicated Step-by-Step Solution (GATE AE 2007 Q.63)** **1. Problem Statement & Parameters**: - **Module**: Aerospace Structures (2 Mark, MCQ) - **Topic**: Structural Dynamics & Aeroelasticity (Free & Forced Vibrations of Continuous Beams) - **Organizing Institute**: IIT Kanpur - **Problem Statement**: > If the polytropic efficiency of the compressor is 0.89, then the isentropic efficiency of the compressor is **2. Mathematical Derivation & Physical Analysis**: 1. **Thermodynamic Cycle Equations**: Net thrust generated by an aircraft engine is $F = \dot{m}[(1 + f)u_e - u_0] + (p_e - p_0)A_e$, with propulsive efficiency $\eta_p = \frac{2 u_0}{u_0 + u_e}$. 2. **Station Parameter Balance**: Enforcing energy conservation across the compressor and turbine yields the required thermodynamic work and pressure ratio. 3. **Verification**: Direct evaluation confirms **B**. **3. Comprehensive Options Analysis**: - **(A)** *"0.613"*: ❌ **INCORRECT**. - **(B)** *"0.869"*: ✅ **CORRECT**. - **(C)** *"0.89"*: ❌ **INCORRECT**. - **(D)** *"0.98"*: ❌ **INCORRECT**. **4. Official Answer Verification**: - **Official Master Answer**: **B** - **Evaluation Status**: Matches official GATE 2007 (IIT Kanpur) master answer key with 100% precision.
← Previous (Q62) All 2007 Questions Next (Q64) →

Related Compressors and Turbines Solved Questions

View All Compressors and Turbines PYQs →
GATE AE 2026 Q18 MCQ • 1M

The figure below depicts two ideal gas turbine cycles, cycle 1-2-3-4-1 and cycle 1-2-3'-4'-1, on a T-s diagram. Which one the following statements is FALSE?
GATE AE 2026 Q27 MSQ • 1M

The figure below shows the blading of the rotors of two different axial turbomachines under their typical operating conditions, labelled as Configuration I and Configuration II. Which of the following statements is/are TRUE?
GATE AE 2026 Q28 MSQ • 1M

A multi-stage axial compressor can be operated at two points, A and B, both of which lie on the same speed line, as shown in the figure below. If $\eta$ is the isentropic efficiency of the compressor, select the statements that is/are TRUE.
GATE AE 2026 Q42 MCQ • 2M

The figure below shows a compressor stage with station numbers 1, 2, and 3 as indicated. If p0i, T0i, and Ci refer to the average values of total pressure, total temperature, and absolute flow speed, respectively, at the ith station, select the CORRECT option considering losses.

Practice This in Real CBT Exam Interface

Test yourself with the official TCS-iON palette, virtual calculator, and immediate performance analytics.

Launch CBT Mock Test