Laminar flow, Turbulence flow , Reynolds number, Use of Reynolds number explained here in easy terms in detail
Blog Content
- Flow Patterns
- Laminar Flow
- Turbulence flow
- Transition flow
- Reynolds number
- Use of Reynolds number.
Interview Questions from this blog
- What is laminar flow, Laminar flow, Transition flow?
- What is Reynolds number?
- How to predict flow pattern with Reynolds number?
- What is use of Reynolds Number?
Flow patterns
There are two types of fluid flow pattern- Laminar flow pattern
- Turbulence flow pattern
- Transition flow pattern
1. Laminar flow pattern
- Laminar flow pattern is a decent flow pattern where all layers of fluids are flowing in parallel without any disturbance.
- It following smooth path for flow. There is no swirls or eddies in flow
- Layers of fluids are flowing in straight region
- Smaller pipes with minimum flow has Laminar flow.
- Laminar flow shear stress dependent on Viscosity of fluid & Independent of density of fluids.
- Laminates is term which refers movement of adjacent fluid particles together.
- It is also known as Streamline flow or Viscous flow.
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| Laminar flow Turbulence flow |
Examples
1. High viscous flow at low flow rates
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| Credits - Quora |
2.Honey dropping with gravity
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| Credits - Quora |
3. Toothpaste coming out
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| Credits - Quora |
Turbulence flow
- Turbulence flow is disturbed flow patterns. Where Layers has Irregular fluctuations.
- Fluids with flow rates in large diameter pipe has this turbulence flow. It creates whirlpool
- Adjacent layers fluids are crossing another fluid layers, totally distorted flow.
- Turbulent flow's shear stress depends on density of fluids.
- When flow consisting lines has more elbows, Instruments and other restrictions it makes more turbulence.
- Turbulence filters available for convert turbulence filter for flow sensors.
- Turbulence flow is also known as Chaotic flow
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| Laminar flow |
Examples
1. Water fall
Transition flow
It is mixed flow pattern containing both types of flow pattern in mixed. |
| Credits - Quora |
Reynolds number
Reynolds number is a flow pattern finding tool. we can analyse flow pattern with this formula.Reynolds number = D * V * ρ / μ
- Re = Reynolds number
- D = Diameter of Pipe, meter
- V = Velocity of Fluids, m/s
- ρ = Density of fluid, kg/m^3
- μ = Viscosity of fluid, kg·m−1·s−1
If
Nu = Nusselt number
Re = Reynolds number
Pr = Preandlt number
Di = Pipe inside Diameter
Nu = Nusselt number
Re = Reynolds number
Pr = Preandlt number
- Reynolds number < 2300 : Laminar Flow.
- 2300 < Reynolds number < 4000 : Transition Flow.
- 4000 < Reynolds number : Turbulence flow.
Use of Reynolds number
Reynolds number is used in- To calculate Shell side heat transfer co efficient.
- To calculate Nusselt number in calculation of Tube side heat transfer co efficient.
The heat transfer coefficient is the heat transferred per unit area.
Tube Side Heat transfer Co-efficient
Sieder-Tate Equation for laminar flow
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| Sieder tate equation |
Nu = Nusselt number
Re = Reynolds number
Pr = Preandlt number
Di = Pipe inside Diameter
µ = Fluid Viscosity of fluid bulk temperature
µW = Fluid Viscosity at pipe wall temperature
Dittus-Bolter Equation for Turbulence flow
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| Dittus bolter equation for tube side heat transfer co efficient in turbulence flow |
Re = Reynolds number
Pr = Preandlt number
µ = Fluid Viscosity of fluid bulk temperature
µW = Fluid Viscosity at pipe wall temperature
Shell side heat transfer co efficient