Chemical Engineering - MCQ Practice Questions

For compressible isothermal flow through a horizontal pipe, which statement is correct?

Which of the following conditions must be satisfied for cavitation to occur in a centrifugal pump?

In open channel flow, the Froude number is defined as Fr = V/√(gD_h), where D_h is the hydraulic depth. When Fr = 1, the flow is classified as:

For flow measurement in a Venturi tube with diameter ratio (D₁/D₂) = 2, what is the diameter ratio for minimum vibration and noise?

A fluid with kinematic viscosity ν = 2×10⁻⁵ m²/s flows over a flat plate at velocity V = 10 m/s. At what plate length does transition from laminar to turbulent flow occur (Re_critical ≈ 5×10⁵)?

In a settling tank (clarifier) with depth H = 2 m, overflow rate = 1 m³/m²·h, and settling velocity of particles = 0.02 m/min, will the particles settle completely?

For a centrifugal pump, cavitation can be prevented by maintaining NPSH above the required value. In 2024-25 industrial practice, what is the typical margin kept above calculated NPSH_required?

A submersed weir has crest length L = 1.5 m and head H = 0.6 m. Using Francis formula for suppressed weir (Q = 1.84 LH^1.5), calculate discharge.

For laminar flow in a circular pipe, the velocity profile is parabolic. What is the relationship between maximum velocity (V_max) and average velocity (V_avg)?

A pitot tube is used for velocity measurement. If the stagnation pressure is 101.5 kPa and static pressure is 100.2 kPa, calculate the fluid velocity (ρ = 1.2 kg/m³).

In a pump, the head developed is 50 m and flow rate is 100 L/s. Calculate the hydraulic power. (Take g = 9.81 m/s²)

For a turbulent pipe flow with friction factor f = 0.032, pipe diameter D = 0.1 m, and velocity V = 3 m/s over length L = 50 m, calculate pressure drop using Darcy-Weisbach equation.

A fluid with density 800 kg/m³ flows through an orifice plate. If pressure drop across orifice is 50 kPa, what is the fluid velocity? (C_d = 0.61, Area ratio β = 0.5)

A boundary layer develops on a flat plate immersed in a flowing fluid. Which of the following correctly describes boundary layer separation?

For an open channel with trapezoidal cross-section, which parameter is used to determine the wetted perimeter?

A sharp-crested weir has a crest length of 2.0 m. If the head over weir is 0.4 m, calculate the discharge using Francis formula. (Use C_d = 0.623)

The Blasius equation for friction factor in turbulent flow is valid for:

Water flows through a pipe at 15°C (ρ = 999 kg/m³, μ = 1.139×10⁻³ Pa·s). If flow rate is 0.05 m³/s through a 0.1 m diameter pipe, is the flow laminar or turbulent?

In open channel flow, the Froude number (Fr) determines the type of flow. For a rectangular channel with depth 0.5 m and velocity 1.5 m/s, calculate the Froude number (g = 9.81 m/s²).

For turbulent flow in smooth pipes, which equation is commonly used to estimate friction factor?