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New! Conveyors in Ventsim DESIGN


Martin Griffith
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Also new in Ventsim DESIGN 5.4: Conveyors!

Ventsim 5 already has a feature to model the heat from exposed waterways (which you can read about elsewhere in the forum), which we have based out design of the conveyor tool on.

The conveyor heat problem is quite a complicated one; there are a lot of factors at play. The heat transferred from the conveyor will depend on:

·        The temperature of the transported ore

·        The mineral type of the transported ore (rock diffusivity, conductivity, density)

·        The temperature of the air around the conveyor

·        The surface roughness of the ore (in fact, the roughness of the ore and the conveyor) which will affect the convective heat transfer from the ore to the air

·        The cross-sectional area of the conveyor and transported ore (which will depend on the velocity of the conveyor, the ore mass flow rate and the ore rock density)

·        And of course the length of the conveyor system.

Additional to this, there is a motor running the conveyor. This motor will generate energy; but where will this energy end up? We’ve assumed that the power from the conveyor motor is dispersed evenly along the conveyor via friction from the rollers as heat, which is also conducted into and conveyed by the conveyor. If the conveyor is lifting the ore any distance, then some energy from the motor is stored as gravitational potential energy and doesn’t add to the heat load. Other factors affecting the heat from the conveyor are how often it is running, is it stopping or starting and is it always fully loaded?

So there are quite a few factors and we’ve tried to include all of them in the Conveyor tool. There being so many parameters and factors, it is a good idea to get parameters as accurate as you can and then seek to calibrate against real measurements.

To build a conveyor, select the airways you want to place the conveyors in and then select Construct Conveyor under the Draw Tool

image.png.2c088c8ac7a48da1885a3b0421e4f903.png

This opens the Construct Conveyor dialog, which includes all of the parameters I discussed above.

image.png.2f6d6de03f148540cfc9b0a4fd008b6c.png

You can specify all of the parameters discussed above, as well as specify what fractions of time the conveyor is running loaded, unloaded or idle. You also need to select an Ore Temperature Method. The simplest option is Constant Temperature. If you want, in the second option you can also set a start and finish temperature, and Ventsim will distribute ore temperatures along the conveyor according to a standard heat transfer function. Lastly, the Calculated Temperature option will adjust the ore temperature during the simulation according to the amount of heat transferred.

Once the conveyor is setup it will appear next to the associated airways according to the offsets (and the width) that you selected during setup, and be automatically included in the Heat Simulation. In the example here, I’ve set my offsets as X = 0 and Y= -5, so my conveyor appears below the airways. I’ve coloured my model by temperature and, since I have my conveyor in a low airflow region of the mine and I’ve generated some very high temperatures.

image.png.9cca5980e495e61866547eccd290d406.png

If you want to switch off the heat from the conveyor, you can simply select it and delete it; or you can go to the Heat Settings and turn them off there, if you still want to keep your built conveyor.

Please don’t hesitate to ask us more about the Conveyor feature, and let us know if you have any questions or experiences to relate

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  • 4 months later...

Hi Martin

Overall works but problem with copying airways (same as my previous problem)

When I create a conveyor the conveyor "airways" are in a group

If I copy the conveyor and attached airways (e.g. a belt road) in wire frame then all the airways and links are copied BUT the two conveyors are linked as a group.

This puts twice as much heat into BOTH sets of attached airways

Can you fix this please.

 

 

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Hi Roy, 

Does the model take into account the difference in cooling from a thicker pile i.e. the skin cools faster than the core ?

Yes, this is correct. The Ore Thickness and Thermal Conductivity (from the Rock type) are used in determining the heat transfer coefficient; the thicker the ore, the lower the heat transfer. Additionally, this thickness (along with the width) is used to represent the conveyor visually in the viewer.

If I copy the conveyor and attached airways (e.g. a belt road) in wire frame then all the airways and links are copied BUT the two conveyors are linked as a group. This puts twice as much heat into BOTH sets of attached airways

We will make a change so that old groups aren't extended when duplicated. The change we made previously does this, but only if every airway copied belongs to the same group (which is not the case when conveyors are being copied along with their partner airways) However, I couldn't come up with a case where the heat was added twice in each set. Are you able to send me an example of this?

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