Compressors and Turbines

Subtopic: Axial Flow Gas Turbines & Blade Cooling

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?

Subtopic: Axial Flow Gas Turbines & Blade Cooling

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?

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

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.

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

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.

Subtopic: Centrifugal Compressors

In a centrifugal compressor, the eye tip diameter is 10 cm. For a shaft rotational speed of 490 rotations per second, the tangential speed at the inducer tip is ___ m/s (rounded off to one decimal place).

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

A multistage axial compressor, with overall isentropic efficiency of 0.83, is used to compress air at a stagnation temperature of 300 K through a pressure ratio of 10:1. Each stage of the compressor is similar, and the stagnation temperature rise across each compressor stage is 20 K. Assume Cp = 1005 J/kg K and  = 1.4 for air. How many stages are there in the compressor?

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

Which of the following statements is/are TRUE for a single stage axial compressor?

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

In the figure shown below, the magnitude of internal force in member BC is ___________ N (rounded off to 1 decimal place).

Subtopic: Centrifugal Compressors

A centrifugal compressor is designed to operate with air. At the leading edge of the tip of the inducer (eye of the impeller), the blade angle is 45o, and the relative Mach number is 1.0. The stagnation temperature of the incoming air is 300 K. Consider  = 1.4. Neglect pre-whirl and slip. The inducer tip speed is ________ m/s (rounded off to the nearest integer).

Subtopic: Axial Flow Gas Turbines & Blade Cooling

In a single-spool aviation turbojet engine, which of the following is the correct relationship between the total work output WT of a^2-stage axial turbine and the total work required WC by a 6-stage axial compressor, neglecting losses?

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

For a stage of a 50% reaction ideal axial flow compressor (symmetrical blading), select the correct statement from the options given.

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

A high-pressure-ratio multistage axial compressor encounters an extreme loading mismatch during starting. Which of the following technique(s) can be used to alleviate this problem?

Subtopic: Centrifugal Compressors

A conventional airplane of mass 5000 kg is doing a level turn of radius 1000 m at a constant speed of 100 m/s at sea level. Taking the acceleration due to gravity as 10 m/s^2, the bank angle of the airplane is degrees.

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

A multistage axial compressor takes in air at $1\text{ atm}, 300\text{ K}$ and compresses it to a minimum of $5\text{ atm}$. The mean blade speed is $245\text{ m/s}$ and work coefficient, $\frac{\Delta C_\theta}{U}$ is $0.55$ for each stage. For air, use $C_p = 1005\text{ J/(kg}\cdot\text{K)}, R = 287\text{ J/(kg}\cdot\text{K)}$ and $\gamma = 1.4$. If the compression is isentropic, the number of stages required is ______ (rounded off to the next higher integer).

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

Q.27 The figure shows three glasses P, Q and R with water and floating ice cube. Glass P has a solid ice cube, glass Q has an ice cube with a small solid steel ball embedded in it and glass R has an ice cube with an air bubble. After the ice cube melts, the level of water in glasses P, Q and R, respectively:

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

Q.54 A jet aircraft weighing 10,000 kg has an elliptic wing with a span of 10 m and area 30 m'. The CD, for the aircraft is 0.025. The maximum speed of the aircraft in steady and level flight at sea level is 100 m/s. The density of air at sea level is 1.225 kg/m', and take g = 10 m/s. The maximum thrust

Subtopic: Centrifugal Compressors

GATE 2019 Aerospace Engineering Q.12 For a single stage subsonic compressor, which of the following statements about the highest possible compressor pressure ratio (CPR) is correct?

Subtopic: Centrifugal Compressors

CPR of an axial compressor < CPR of centrifugal compressor. (C) CPR of an axial compressor = CPR of centrifugal compressor. (D) CPR of any value can be attained with either an axial or a centrifugal compressor. Q.13 For a beam subjected to a transverse shear load through its shear center,

Subtopic: Axial Flow Gas Turbines & Blade Cooling

In an ideal gas turbine cycle, the expansion in a turbine is represented by

Subtopic: Axial Flow Gas Turbines & Blade Cooling

In an ideal Brayton cycle for a gas turbine engine, which of the following processes correctly represents the heat addition and rejection?

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

The degree of reaction ($R$) of an axial flow compressor stage is defined as the ratio of:

Subtopic: Centrifugal Compressors

The relative velocity of air leaving a straight radial impeller of a centrifugal compressor is 100 m/s. If the impeller tip speed is 200 m/s, for a slip free operation, the absolute velocity (in m/s) at the impeller exit is _________ (accurate to one decimal place).

Subtopic: Centrifugal Compressors

The relative velocity of air leaving a straight radial impeller of a centrifugal compressor is 100 m/s. If the impeller tip speed is 200 m/s, for a slip free operation, the absolute velocity (in m/s) of air at the impeller exit is _________ (accurate to one decimal place).

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

The ninth and the tenth of this month are Monday and Tuesday

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

It is _______ to read this year's textbook than the last year's. Choose the correct option to fill in the blanks:

Subtopic: Axial Flow Gas Turbines & Blade Cooling

Air, at 450 K stagnation temperature and at a rate of 50 kg/s, enters an axial turbine stage and leaves at 350 K stagnation temperature. Taking specific heat at constant pressure $C_p = 1005$ J/(kg K), the power output (in MW) from the turbine is _________ (round off to 2 decimal places).

Subtopic: Centrifugal Compressors

A centrifugal compressor requires 1800 kW of power to compress 10 kg/s of air entering at 300 K stagnation temperature. Taking specific heat $C_p = 1000$ J/(kg K), the stagnation temperature (in K) of air leaving the compressor is _________ K.

Subtopic: Axial Flow Gas Turbines & Blade Cooling

Combustion in gas turbine engines is ideally represented as the following process:

Subtopic: Axial Flow Gas Turbines & Blade Cooling

For a given fuel flow rate and thermal efficiency, the take-off thrust for a gas turbine engine burning aviation turbine fuel (considering fuel-air ratiof<<1) is

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

For a fifty percent reaction axial compressor stage, following statements are given: I. Velocity triangles at the entry and exit of the rotor are symmetrical II. The whirl or swirl component of absolute velocity at the entry of rotor and entry of stator are same. Which of the following options are correct?

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

The thrust produced by a turbojet engine

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

If [ ]     - -= 4 3 3 3A . Then ( )] [ 3 ] [ 7 ] [det 2 I A A- + - is

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

For the periodic function given by { 0, 2 0 , 2) ( < < - - < <= x xx f $\pi \pi$ with ) ( ) 2 (x fx f = +$\pi$ , using Fourier series, the sum + - + - =7 1 5 1 3 11s converges to

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

Let 22 2 ˆˆˆˆ ˆ ˆ() ( ) S I yz i zx j xy k x i y j z kd S    , where S denotes the surface of the sphere of unit radius centered at the origin. Here ˆˆˆ, a n d ij k denote three orthogonal unit vectors. The value of I is ____________

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

Given that the Laplace transform, ࣦ1() ate s a  then ࣦ  53s i n h 5tet =

Subtopic: Centrifugal Compressors

If $3 \le X \le 5$ and $8 \le Y \le 11$, then which of the following options is TRUE?

Subtopic: Axial Flow Gas Turbines & Blade Cooling

All engineering students should learn mechanics, mathematics and how to do computation. I II III IV Which of the above underlined parts of the sentence is not appropriate?

Subtopic: Centrifugal Compressors

Choose the most appropriate alternative from the options given below to complete the following sentence: I ___ to have bought a diamond ring.

Subtopic: Axial Flow Gas Turbines & Blade Cooling

Choose the most appropriate alternative from the options given below to complete the following sentence: To those of us who had always thought him timid, his ___ came as a surprise.

Subtopic: Axial Flow Gas Turbines & Blade Cooling

For a gas turbine engine, the specific work output is maximum when the compressor temperature ratio equals:

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

For an axial compressor stage with 50% reaction, the stator and rotor blade shapes are:

Subtopic: Centrifugal Compressors

Choose the word from the options given below that is most nearly opposite in meaning to the given word: Deference

Subtopic: Axial Flow Gas Turbines & Blade Cooling

In how many ways 3 scholarships can be awarded to 4 applicants, when each applicant can receive at most one scholarship?

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

For a multi-stage axial compressor with consiant diameter hub

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

The function f(x, y) = 2°+ y-sy- 35 has an extremum al the point

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

What is the stagnation pressure ratio (Pes) for this compressor?

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

d Which of the following statements is true ?

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

Which of the following statements is TRUE regarding aircraft stability?

Subtopic: Axial Flow Gas Turbines & Blade Cooling

The turbine power per unit mass flow is

Subtopic: Axial Flow Gas Turbines & Blade Cooling

The mass flow rate of fuel is

Subtopic: Centrifugal Compressors

Air enters through the eye of a centrifugal compressor with a stagnation temperature 300 K and exits the compressor with a stagnation temperature 424 K. If the isentropic efficiency of the compressor is 0.81 and the ratio of specific heats of the flowing gas (assumed as constant) is 1.4, then the pressure ratio across the compressor is

Subtopic: Centrifugal Compressors

Which one of the following statements is true?

Subtopic: Centrifugal Compressors

The system shows the following type of coordinate coupling

Subtopic: Axial Flow Compressor Stage Dynamics & Stall

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