JNTU
JNTU B.Tech III AERODYNAMICS II Previous Question Paper (July/August - 2023 - R13)
Note: i) Question paper consists of Part A, Part B.
ii) Part A is compulsory, which carries 25 marks. In Part A, Answer all questions.
iii) In Part B, Answer any one question from each unit. Each question carries 10 marks and may have a, b as sub questions.
PART - A
What are the fundamental requirements for a quasi-equilibrium process to take place?
Answer
A quasi-equilibrium process, also known as a quasi-static process, occurs when a system proceeds through a series of equilibrium states such that the system remains infinitesimally close to thermodynamic equilibrium at all times. The fundamental requirements are that the process must occur sufficiently slowly so that the internal properties of the system (such as pressure, temperature, and density) remain uniform throughout, and the driving force for the process must be infinitesimally greater than the opposing resistance.
The flow energy of 0.124 m3/min of a fluid crossing a boundary to a system is 18 kW. Find the pressure at this point.
Answer
The flow energy (or flow work) per unit time is given by the product of the pressure and the volumetric flow rate. The relationship is expressed as:
Given the flow energy rate (W) is 18 kW (18,000 J/s) and the volumetric flow rate (Q) is 0.124 m3/min, we first convert the flow rate to SI units (m3/s):
Substituting these values into the formula:
The pressure at this point is approximately 8.71 MPa.
How does the molecular weight of a gas affect its speed of sound?
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Find the strength of a shock when normal shock appears at M = 2.
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Draw the velocity triangles upstream and downstream of an oblique shock wave?
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Air having a Mach number of 1.5 undergoes a deflection of a convex corner of 100. Find the Mach number at the corner.
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Using Prandtl-Glauert rule, calculate the lift coefficient for an NACA 2412 airfoil at 50 angle of attack in a Mach 0.6 free stream. Given cl0 = 0.75.
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“Sonic flow can only occur at a throat or minimum area of the flow”. Use area–velocity relation to justify the statement.
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What is the advantage of delta wing in a supersonic flow?
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Explain the principle of limited upstream influence in supersonic flow.
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PART - B
Which thermodynamic property remains constant in a Joule-Kelvin expansion process? Is Joule-Kelvin expansion a reversible or irreversible process?
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Prove that Joule – Thomson co-efficient μ = (∂T/∂p)h = (T/2Cp)[∂/∂T (V/T)]p
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A mass of gas is compressed in a quasi-static process from 80 kPa, 0.1 m3 to 0.4 MPa, 0.03 m3. Assume that the pressure and volume are related by pvn = constant, find the work done by the gas system.
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A refrigeration plant for a food storage operates as a reversed Carnot heat engine cycle. The store is to be maintained at a temperature of -50C and the heat transfer from the store to the cycle is at the rate of 5 kW. If heat is transferred from the cycle to the atmosphere at a temperature of 250C, calculate the power required to drive the plant.
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Show that an accelerating flow can be obtained a) if the flow area is increased in a supersonic flow and b) if the flow area is decreased in a subsonic flow.
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Show that pressure and temperature always increases across a shock.
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Derive the relationship connecting the upstream Mach number, deflection angle and shock wave angle for an oblique shock wave.
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A flat plate kept at 150 angle of attack to a supersonic stream at Mach 2.4. Solve the flow field around the plate using shock-expansion theory.
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Derive a closed form expression for mass flow rate through the choked nozzle.
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Consider a subsonic compressible flow in Cartesian flow coordinates where the velocity potential is given by φ(x, y) = V∞x + (70/√(1 - M∞2)) e-2π√(1 - M∞2) y sin 2πx. If the free stream properties are given by V∞ = 300 m/s, p∞ = 1 atm and T∞ = 300 K, calculate the M, p and T at the location (x, y ) = (0.04 m, 0.04 m).
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Derive an expression for the linearized supersonic pressure coefficient.
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Using linearized theory, calculate the lift and drag coefficients for a flat plate at a 100 angle of attack in a Mach 2.5 flow.
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