B.TECH - Semester 7 gas dynamics Question Paper 2020 (sep)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- Explain Mach angle, Mach cone and sonic boom.
- What do you mean by the stagnation speed of sound?
- What do you mean by impulse Function? Bring out its relationship with Mach Number.
- Write down the expression for stagnation to static ratios of temperature and pressures for 1-D isentropic flow.
- Explain the over expansion and under expansion in nozzle flow.
- Explain why the normal shock cannot occur in subsonic flows.
- Locate the maximum entropy point in Fanno flow on h-s diagram.
- Explain Oblique shocks.
- Explain the concept of Adiabatic Recover factor in flow measurements
- Explain the working of a Kiel probe. Answer any one full question from each Module. Each question carries 20 marks.
- (a) Derive an expression for the reference Mach number [ $\mathrm{M}^{\star}$ ] in terms of the Mach number [M] of the flow.
- (b) The speed indicator of an aero plane whose speed meter is calibrated without considering the effect of compressibility on dynamic properties. The speed meter registers a speed of $1000 \mathrm{~km} / \mathrm{hour}$ at an altitude of 5000 m . Dete...
- (a) Derive the momentum equation using the control volume approach.
- (b) Nitrogen at a temperature of $350^{\circ} \mathrm{C}$ and a pressure of 5 bar is flowing through a duct with a velocity $250 \mathrm{~m} / \mathrm{s}$. Determine the Mach number of the flow.
- (a) Derive an expression for the exit to throat area ratio of a converging diverging nozzle in terms of the exit Mach number of the flow.
- (b) Air enters a variable area duct at a temperature of 300 K , pressure of 0.4 bar and a velocity of $200 \mathrm{~m} / \mathrm{s}$. The area of cross section at the entry of the duct is $500 \mathrm{~cm}^{2}$ and the exit area is $350 \mathrm{~cm}^...
- (a) Derive the Prandtl- Meyer equation in connection with the normal shock.
- (b) A convergent - divergent nozzle has an exit to throat area ratio of 3.0. Air is entering directly from a combustion chamber at a pressure of $700 \mathrm{kN} / \mathrm{m}^{2}$ and temperature of $90^{\circ} \mathrm{C}$. Due to its operation at it...
- (a) Explain the changes happening in both the subsonic and supersonic Rayleigh flow until the limiting condition using the h-s diagram. Locate the maximum entropy and the maximum enthalpy point in Rayleigh flow on h-s diagram.
- (b) Air is passing at a rate of $8 \mathrm{~kg} / \mathrm{sec}$ through an insulated circular pipe line. The entry pressure. temperature and Mach number of the air are 3 bar, 300 K and 0.15 respectively. The coefficient of friction of the pipe is 0.0...
- (a) Explain the changes happening in both the subsonic and supersonic Fanno flow until the limiting condition using the h -s diagram. Locate the maximum entropy point in Fanno flow on h-s diagram.
- (b) Air enters a constant area pipe with velocity of $200 \mathrm{~m} / \mathrm{s}$, temperature of $100^{\circ} \mathrm{C}$ and pressure of 6 bar . If $220 \mathrm{~kJ} / \mathrm{kg}$ of heat is added to the pipe for the entire length, find
- (i) pressure at the exit, (ii) Mach number of the air at the exit, (iii) change in stagnation pressure and (iv) the change in entropy of the air.
- (a) Explain the working of a Prandtl Pitot- static tube. Explain how itsimultaneously measures the static and the stagnation pressure. 10
- (b) Explain the use of hot wire anemometer. Differentiate between the constanttemperature and the constant current hot wire anemometers.10
- (a) What is the use of the wind tunnel? Explain how closed type wind tunnel differs from an open type wind tunnel using suitable diagrams. 10
- (b) Explain the working of a shock tube. 10 ( $\mathbf{4} \boldsymbol{\times} \mathbf{2 0} \boldsymbol{=} \mathbf{8 0}$ Marks)