Jump to content
Ventilation & Flow Simulation Forums

Activity track anomaly


R Viljoen

Recommended Posts

Good day

It appears as though sensible heat calculations in v5.4.7.0 is giving errors. 

Suppose one were to include diesel vehicles and secondary fans on the same activity track or as two distinct tracks but assigned to the same airways (e.g. series ventilation circuit). For each heat load, a preset is created in the usual way, i.e. point diesel power and point sensible source. Assume a truck and fan with a rated power of 500 kW and 100 kW, respectively. For simplicity, utilisation factors of 35% and 100% were chosen such that the thermal heat load (per unit) equals the rated power (global diesel efficiency setting = 35%). With a single truck plus five fans are added to a single track on a 500m(L) horizontal drive and 100 m³/s of airflow passing, the heat summary page shows a sensible heat load of 1240 kW, as opposed to 1000 kW (1x500 + 5x100). The same occurs when two separate tracks are created. However, when the heat sources are modelled in isolation the expected values result (500 kW in either case).

Any thoughts?

Link to comment
Share on other sites

Hi,

Thanks for the message. Apologies, this looks like a bug in the addition of the diesel and sensible heat sources on the tracked airways. We are putting out a patch later today, we will try to fix this in that version. 

For now, to get around it, place the heat source for the secondary fans on the airways (via the Heat tab of the Edit Box) rather than on the track. 

A couple of things to note, if you have fans included in your model, then Ventsim will automatically add the heat from the fan in the Heat Simulation. You would only add heat in this way if you weren't including the secondary fans in your Air Simulation model.

Thanks again, I will post here again when the fix is available.

Link to comment
Share on other sites

Hi Martin & Developers

Thanks for the swift reply and patch - the issue appears to be resolved.

I'm aware that secondary fan heat (either via fix flows or from fan curves) is automatically included. For context, the method of using activity tracks to model several heat sources at once is particularly handy in desktop studies of shallow, series-ventilated mines where all the heat reports back to the decline, and ultimately, the bottommost return connection. With minimal error (high strata/broken rock heat load cases excepted), one could simply ignore creating the working levels and the effort involved with constructing ventilation ducts/fans to perform quick heat/energy balances or check where decline conditions exceed some threshold value (e.g. >26.0°Cwb). In my opinion, it is far simpler to create several activity tracks in the appropriate locations and to update equipment counts (e.g. for what-if scenarios) via the track editor compared to manually inserting these heat loads, unless of course the parameter(s) of interest are desired at discreet points.

Keep up the good work.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...