B.TECH - Semester 7 gas dynamics Question Paper 2008 (dec)
Practice authentic previous year university questions for better exam preparation.
Sample Questions
- What do you mean by continuum flow? Define Knudsen number.
- Explain adiabatic steady flow ellipse.
- Discuss the effects of Mach number on compressibility.
- Show that $\mathrm{M}=1$ at the point of maximum entropy for Rayleigh flow.
- Explain Choking in Fanno flow.
- Explain Rayleigh flow clearly stating assumptions. Give examples.
- Explain why shock is not possible in a subsonic flow.
- Write a note on supersonic flow over a compression and expansion corner.
- What is wedge probe? Explain the working of wedge probe with a sketch.
- How does a Prandtl-pitot tube simultaneously measure the static and stagnation pressure? ( $10 \times 4=40$ Marks)
- (a) Derive the energy equation for a control volume. State the assumptions.
- (b) A conical diffuser has an inlet diameter of 40 cm and exit diameter of 80 cm . Air enters the diffuser with a static pressure of 200 kPa and a static temperature of $37^{\circ} \mathrm{C}$. The average velocity of flow at inlet to the diffuser is...
- (i) the mass flow rate, (ii) properties at the section.
- (a) Derive the relation between Mach number M and dimensionless Mach number $\mathrm{M}^{*}$.
- (b) The pressure, temperature and Mach number at the entry of a flow Passage are 2.45 bar, 26.5 C and 1.4 respectively. If the exit Mach number is 2.5 determine for adiabatic flow of a perfect gas $\gamma=1.3, \mathrm{R}=0.469 \mathrm{~kJ} / \mathrm{...
- (i) stagnation temperature, (ii) temperature and velocity of gas at exit, and (iii) the flow rate per square metre of the inlet cross-section.
- (a) Show that the upper and lower branches of a Fanno curve represent subsonic and supersonic flows respectively. Prove that at the maximum entropy point, the Mach number is unity and all processes tend to approach this point.
- (b) Air flows through a constant area duct. Pressure and temperature of the air at inlet to the duct are 100 kPa and $10^{\circ} \mathrm{C}$ respectively and the inlet Mach number is 2.8. Heat is transferred to the air as it flows through the duct an...
- (a) Derive the following relation for a Rayleigh flow. $$ \frac{Q_{\max }}{C_{p} T_{1}}=\frac{\left(1-M^{2}\right)^{2}}{2(1+\gamma) M^{2}} $$
- (b) A convergent divergent nozzle having a throat diameter of 7.5 supplies air to an insulated duct of diameter 15 mm . The stagnation properties of air at entry of the nozzle are 7.5 bar and 300 k . The flow through the nozzle is isentropic. The mea...
- (a) With a neat sketch explain the working of an interferometer. 10
- (b) Derive Rankine-Hugonit relation.
- (a) With a neat sketch explain the working of a constant temperature type not-wire anemometer.
- (b) The exit to entry area of a divergent duct is $1.4: 1$. The Mach number at inlet and exit are 1.7 and 0.5 respectively. A normal shock occurs in the duct. Assuming isentropic flow of air before and after the shock, determine.
- (i) location of the normal shock in the duct, (ii) percentage loss in stagnation pressure, and (iii) change in entropy. M 6694