Convective heat transfer coefficient in channel

In summary, to measure the heat transfer coefficient in a block channel with a trapezoid object inside, the hydraulic diameter (Dh) needs to be calculated. This can be done by measuring the height and two base lengths of the trapezoid and using them to calculate the area and perimeter, which can then be plugged into the equation Dh = 4A/P.
  • #1
leonita
4
0
Hi,
I need to measure heat transfer coefficient in the block channel. However, the block is not general block. Inside block, there is trapezoid object. So, water flow rate in the first is low speed because big square.
Then the square size will decrease then the speed is high.
Do you know how to measure hydraulic diameter (Dh) of it?
 

Attachments

  • tanya reynold.png
    tanya reynold.png
    4.7 KB · Views: 470
Engineering news on Phys.org
  • #2
The hydraulic diameter (Dh) of any channel is calculated using the equation:Dh = 4A/Pwhere A is the cross-sectional area of the channel and P is its wetted perimeter. To calculate the hydraulic diameter for a trapezoid channel, you will need to measure the height (h) and the two base lengths (a & b) of the trapezoid and then calculate the area and perimeter. The area can be calculated using the formula:A = ((a+b)/2)*h and the perimeter can be calculated using the formula:P = a + b + 2 √((a/2)² + h²)Once you have these measurements, you can plug them into the equation above to calculate the hydraulic diameter.
 

What is the convective heat transfer coefficient?

The convective heat transfer coefficient is a measure of the rate at which heat is transferred between a solid surface and a fluid, typically a gas or liquid. It takes into account factors such as fluid velocity, temperature difference, and surface area.

How is the convective heat transfer coefficient calculated?

The convective heat transfer coefficient can be calculated using the following equation: h = Q / (A * ΔT), where h is the convective heat transfer coefficient, Q is the heat transfer rate, A is the surface area, and ΔT is the temperature difference between the surface and the fluid.

What factors affect the convective heat transfer coefficient?

The convective heat transfer coefficient is affected by a variety of factors, including fluid properties (such as density and viscosity), fluid flow conditions (such as velocity and turbulence), and surface characteristics (such as roughness and shape).

What is the significance of the convective heat transfer coefficient in channel flow?

In channel flow, the convective heat transfer coefficient is important in determining the rate at which heat is transferred between the channel walls and the fluid. It is crucial in many industrial processes, such as in heat exchangers and cooling systems, where efficient heat transfer is necessary for optimal operation.

How can the convective heat transfer coefficient be increased?

The convective heat transfer coefficient can be increased by increasing the flow rate of the fluid, increasing the temperature difference between the surface and the fluid, or by modifying the surface characteristics to enhance heat transfer (e.g. through the use of fins or surface coatings). It can also be improved by reducing any obstructions or turbulence in the fluid flow.

Similar threads

Cooling nozzle - convection power
    • Mechanical Engineering
Replies
5
Views
1K
Laminar flow in a tube, heat transfer coefficient-sanity check
    • Mechanical Engineering
Replies
4
Views
1K
A Practical use of an overall heat transfer coefficient?
    • Thermodynamics
Replies
14
Views
1K
How Long Should My Double Pipe Heat Exchanger Be for a 22kW Capacity?
    • Mechanical Engineering
Replies
2
Views
1K
What is the most accurate way to calculate heating in a waterjet catcher tank?
    • Mechanical Engineering
Replies
7
Views
1K
Engineering Average heat transfer coefficient (forced convection)
    • Engineering and Comp Sci Homework Help
Replies
6
Views
2K
How to design hydraulic system and size cooler
    • Mechanical Engineering
Replies
6
Views
1K
Convective heat transfer coefficients of fuel oil?
    • Mechanical Engineering
Replies
2
Views
3K
Ice will melt faster which case -- over or below hot block?
    • Mechanical Engineering
Replies
14
Views
2K
Overall heat transfer coefficient for water cooling
    • Mechanical Engineering
Replies
2
Views
2K

Hot Threads

Recent Insights

Back
Top