📘 Fluid Transport – Full Summary

🧭 1. Overview of the Topic

The lecture covers how liquids are transported in industrial systems, focusing on:

• Pipes (transport)
• Valves (control)
• Pumps (energy input)
• System design (dimensioning)

👉 Core goal: Ensure efficient, stable, and cost-effective fluid movement

💧 2. Required Head / Pressure to Move Liquid

🔑 Key idea: Head

“Head” = energy per unit weight of fluid (often in meters)

It includes:

• Height difference (gravity)
• Pressure difference
• Friction losses

Components:

• Friction losses → resistance in pipes
• Pressure difference → between start and end
• Level difference → elevation change

👉 Total head = everything the pump must overcome

🧪 3. Specific Gravity (S.G.)

• Ratio of fluid density to water
• Water = 1

👉 Important because:

• Pressure and energy depend on density
• Heavier fluids require more energy to move

🚰 4. Pressure Loss in Pipes

Causes:

• Friction with pipe walls
• Flow disturbances

Flow types:

• Laminar flow → smooth, low resistance
• Turbulent flow → chaotic, high resistance

Friction coefficient:

• Industrial approximation:
  • ( C_f = 0.04 \cdot Re^{-1/6} )
• Typical turbulent:
  • ( C_f ≈ 0.005 )

👉 Lower friction = better efficiency

🧱 5. Pipe Roughness

• Rough pipes → more turbulence → more loss
• Smooth pipes → less energy loss

👉 Important in long pipelines

🔄 6. Losses from Fittings (Image/Table Slide)

Even if pipes are ideal, fittings add losses:

• Bends
• Valves
• Constrictions

Each contributes a “velocity head loss” (n)

Examples:

• 90° bend → moderate loss
• Globe valve → very high loss
• Fully open gate valve → very low loss

👉 Takeaway: Fittings can dominate total losses in complex systems

🧮 7. Pump Head Calculation (Example Slide)

Given:

• Pressure difference (P1 → P2)
• Height difference (Z1 → Z2)
• Pipe length & diameter
• Velocity
• Friction factor

👉 You calculate: Total head required from the pump

This combines:

• Pressure + elevation + friction + fittings

⚠️ 8. Pipe Sizing (Very Important Concept)

Too wide pipes:

• Expensive (high CAPEX)
• Low velocity → risk of sedimentation

Too narrow pipes:

• High friction losses
• High energy consumption

👉 Trade-off between CAPEX vs OPEX

⚡ 9. Optimum Pipe Velocity

Typical ranges depend on fluid type Rule of thumb:

👉 Optimal diameter: D = 0.0038 \cdot \sqrt{\text{flow (m³/h)}}

📏 10. Standard Pipe Sizes (DN)

• Pipes come in standardized diameters
• You select closest available size

👉 Design is not continuous — it’s discrete

🚪 11. Valves (Flow Control)

🎯 Purpose:

• Start/stop flow
• Control flow rate
• Prevent backflow
• Prevent overpressure

🔘 Types of Valves

1. Gate Valve

• On/off only
• Low pressure loss when open
• Must be fully open or closed

👉 Used when minimal resistance is needed

2. Ball Valve

• Fast on/off
• Good for dirty fluids
• Straight flow path

👉 Very common in industry

3. Plug / Three-Way Valve

• Can redirect flow
• Used for switching paths

4. Globe Valve

• Good for flow control
• High pressure loss (flow changes direction)

👉 Precise but inefficient

5. Needle Valve

• Very precise control
• Low flow rates

6. Check Valve

• Prevents backflow
• Works automatically

7. Safety Valve

• Releases pressure to avoid explosions

📉 Pressure Loss Table (Important Slide)

Shows how different valves impact flow

👉 Key insight:

• Partially closed valves → huge losses
• Globe valves → very high resistance

🔌 12. Pumps

🎯 Purpose:

• Move fluid (flow, Q)
• Increase pressure (head, Δp)

⚡ Power Consumption

Theoretical: P = Q \cdot \Delta p

Actual: P_{\text{actual}} = \frac{P}{\eta}

👉 Efficiency matters a lot

🔧 13. Pump Types

1. Diaphragm Pump

✔ High pressure ✔ Handles viscous fluids ❌ Pulsating flow

2. Gear Pump

✔ High pressure ✔ Good for oils ❌ Needs lubrication

3. Peristaltic Pump

✔ Handles aggressive/dirty fluids ✔ Simple ❌ Low pressure

4. Centrifugal Pump (MOST IMPORTANT)

✔ Most widely used ✔ Continuous flow ❌ Not always self-priming

👉 Industrial standard

📈 14. Pump Curves (Image Slides Explained)

Shows relationship between:

• Flow (Q)
• Head (H)

👉 As flow increases → head decreases

Also depends on:

• Rotor size
• Speed

🔋 15. Pump Efficiency

• Pumps have optimal efficiency region
• Operating outside it = wasted energy

👉 Always match pump to system curve

🧠 16. NPSH (Critical Concept)

Net Positive Suction Head

👉 Prevents cavitation (bubble formation)

Condition: NPSH_ > NPSH_

Factors:

• Pressure at inlet
• Vapor pressure
• Friction losses

👉 Cavitation damages pumps

🔗 17. Pumps in Parallel vs Series

Parallel Pumps:

• Increase flow
• Same head

Series Pumps:

• Increase head
• Same flow

👉 Used depending on system needs

🧪 18. Compressors

• Same principle as pumps
• Used for gases

🏭 19. Reactor Dimensioning (Concept Slide)

Design depends on:

• Flow rates
• Reaction rates
• Mode (batch vs continuous)

🧫 20. Fermentation Case (Applied Engineering)

Goal:

Separate ethanol using membrane filtration

🔬 Membrane Properties:

• Permeability: 80 LMH/bar
• Desired flux: 40 LMH 👉 Requires 0.5 bar pressure

📐 Membrane Area Results:

• Batch: 0 m²
• Continuous (Di = 0.2 h⁻¹): 22.4 m²
• Continuous (Di = 1 h⁻¹): 222.4 m²

👉 Higher throughput → much larger system

🚿 Flow Requirements:

Flow per membrane area:

• 10 m³/h per m²

So:

• 22.4 m² → 224 m³/h
• 222.4 m² → 2224 m³/h

🔌 Pump Design:

• Head ≈ 6 m
• Multiple pumps needed:

Example:

• Small system → 2 pumps
• Large system → 20 pumps

💸 Energy Cost:

• Each pump ≈ 3.346 kW
• ~1070 EUR/year

Total:

• Small system → 2140 EUR/year
• Large system → 21400 EUR/year

🎯 Key Takeaways

1. Fluid transport = energy balance problem

You must overcome:

• Friction
• Height
• Pressure

2. Design trade-offs are everywhere

• Pipe size: CAPEX vs OPEX
• Valve type: control vs loss
• Pump type: efficiency vs function

3. Pumps are central

• Must match system curve
• Efficiency determines cost

4. Real systems are complex

• Fittings matter a lot
• Cavitation must be avoided
• Scaling dramatically increases cost