Math Problem Statement

A bottling plant has a pipe that can fill up 75,000 worth of 500 [mL]-bottles per hour. Two points in the pipe, XX and YY, are separated by a height of 5.00 [m] and have respective diameters: dX=dX= 5.80 [cm] and dY=dY= 1.50} [cm]. (Assume fluid is oil, ρoil=ρoil= 912 [kg/m] 33.  What is the pipe's mass flow rate μμ and volume flow rate QQ?

Solution

To solve the problem, we need to calculate the volume flow rate (Q) and the mass flow rate (ṁ).

Step 1: Interpret the Given Information

  1. Flow rate for bottles: Q=Total volume per hourtime=75000×500 mL1 hourQ = \frac{\text{Total volume per hour}}{\text{time}} = \frac{75000 \times 500 \text{ mL}}{1 \text{ hour}}. Since 1 mL=106 m31 \text{ mL} = 10^{-6} \text{ m}^3: Q=75000×500×106 m3/hour.Q = 75000 \times 500 \times 10^{-6} \text{ m}^3/\text{hour}. Convert to m³/s: Q=75000×500×1063600 m3/s.Q = \frac{75000 \times 500 \times 10^{-6}}{3600} \text{ m}^3/\text{s}. Simplifying: Q=10.42×103 m3/s=0.01042 m3/s.Q = 10.42 \times 10^{-3} \text{ m}^3/\text{s} = 0.01042 \text{ m}^3/\text{s}.

  2. Volume Flow Rate: Q=0.01042m3/sQ = 0.01042 \, \text{m}^3/\text{s}.


Step 2: Mass Flow Rate

The mass flow rate m˙\dot{m} is given by: m˙=ρoilQ.\dot{m} = \rho_{\text{oil}} \cdot Q. Given ρoil=912kg/m3\rho_{\text{oil}} = 912 \, \text{kg/m}^3 and Q=0.01042m3/sQ = 0.01042 \, \text{m}^3/\text{s}: m˙=9120.01042=9.50kg/s.\dot{m} = 912 \cdot 0.01042 = 9.50 \, \text{kg/s}.


Step 3: Verify Velocity at Points XX and YY (Bernoulli's Principle)

The velocity at each point can be calculated using the continuity equation: AXvX=AYvY,A_X v_X = A_Y v_Y, where AX=π(dX/2)2A_X = \pi (d_X/2)^2 and AY=π(dY/2)2A_Y = \pi (d_Y/2)^2.

  1. Cross-sectional areas:

    • For dX=5.80cm=0.058md_X = 5.80 \, \text{cm} = 0.058 \, \text{m}: AX=π(0.058/2)2=π(0.029)2=2.64×103m2.A_X = \pi (0.058/2)^2 = \pi (0.029)^2 = 2.64 \times 10^{-3} \, \text{m}^2.
    • For dY=1.50cm=0.015md_Y = 1.50 \, \text{cm} = 0.015 \, \text{m}: AY=π(0.015/2)2=π(0.0075)2=1.77×104m2.A_Y = \pi (0.015/2)^2 = \pi (0.0075)^2 = 1.77 \times 10^{-4} \, \text{m}^2.
  2. Velocities: Using Q=AvQ = A \cdot v, we solve for vXv_X and vYv_Y:

    • At XX: vX=QAX=0.010422.64×103=3.95m/s.v_X = \frac{Q}{A_X} = \frac{0.01042}{2.64 \times 10^{-3}} = 3.95 \, \text{m/s}.
    • At YY: vY=QAY=0.010421.77×104=58.9m/s.v_Y = \frac{Q}{A_Y} = \frac{0.01042}{1.77 \times 10^{-4}} = 58.9 \, \text{m/s}.

Final Answer

  1. Volume Flow Rate QQ: 0.01042m3/s0.01042 \, \text{m}^3/\text{s}.
  2. Mass Flow Rate m˙\dot{m}: 9.50kg/s9.50 \, \text{kg/s}.

Let me know if you'd like further clarifications or detailed steps!


Related Questions:

  1. How does the velocity difference between XX and YY impact pressure drop in the pipe?
  2. Can Bernoulli’s equation be applied to calculate the pressure difference?
  3. What is the kinetic energy difference between XX and YY?
  4. How would the mass flow rate change if the density of oil increased?
  5. What happens to the flow rates if dXd_X is reduced by 50%?

Tip:

Always convert flow rates to consistent units (e.g., m3/s\text{m}^3/\text{s}) before proceeding with calculations!

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Math Problem Analysis

Mathematical Concepts

Fluid Dynamics
Volume Flow Rate
Mass Flow Rate
Continuity Equation
Bernoulli's Principle

Formulas

Volume flow rate Q = Total volume / Time
Mass flow rate ṁ = ρ × Q
Cross-sectional area A = π(d/2)^2
Velocity v = Q / A

Theorems

Continuity Equation
Bernoulli's Principle

Suitable Grade Level

Undergraduate (Physics or Engineering)