Multi Layer Coil for Heat Exchanger- Making.

Multi Layer Coil is a tube designed to transfer heat effectively in heat exchanger or other devices. Also I have calculation to prove that this is effective than ordinary single coil for same lengths. Model can be downloaded Multi Layer Coil- Heat Exchanger. Native formats are also available.

1. Step 1: Helix Creation

Base sketch for coil is made using helix command under wireframe and surface workbench. For helix one should have a start point and axis. For axis I will use default coordinates.

Create a point on Y axis at 50 mm

Now offset a plane at particular distance say 80 mm. Then create a helix (c: helix) with Z axis and set pitch as 5 mm and height as 80 mm.

Next start sketching on the plane that was created. Make sure to project the end point near to plane and circle.

Now time to create an concentric circle of suitable radius say 60 mm. Then place a point straight opposite to the early point on circle drawn.

Draw circle connecting two points tangentially. This step is important. You may have to use proper constrains to get tangency. You can use 3 point circle.

Trim off the older circles and but be sure of direction of helix.

So after trimming out circle and deleting un wanted points, your curve should look like:

Now time for another helix with the end point as starting point create helix for pitch 5 mm and height 80 mm.

You can repeat as many times for other concentric appeal (I have colored to differentiate).

2. Step 2: Rib the Circle

After proceeding with sketch create a line tangential to end points to some distance say 100 mm.

Join all the three helix and two lines using join command.

Form any one end of line create a plane and draw circle on that plane of diameters 4.6 mm and 3 mm.

Time for magic.....

Using rib command select the circle and helix sketch, after few seconds you should a tube coming out to be beautiful.

3. Step 3: Render

I used both Creo 3.0 and CATIA v5 to render which came out to be pretty well.

4. Step 4: Time for Calculation

According to Law of Convection, Q = h A (T1-T2). Let Q1 denote ordinary tube of same height say 80 mm with radius 70 mm. Q2 denotes our model with same parameter.

Then in same environment, h, T1, T2 will be constant,

There by, Q1/Q2 = A1/A2 => Q1/Q2 = 0.00007/0.00018 (m3) => Q1/Q2 = 0.38889 or Q2/Q1 = 2.5714

<Volumes have been calculated Measure Inertia command.

So this design is capable of transferring 2.5 time heat than it's predecessor's.

May be this design might be hard to fabricate, manufacture and costly it provides a good result.