Steam Generation Error

[Peter Newell]

Hi,

I believe that I have found two errors in the MSTSSteamLocomotive.cs.

i) Line 115 - "CylinderDiammeter" has two m's, whereas it should only have one.

ii) Line 627 - I believe that the steam generation (SG) rate shown in the HUD view is incorrect.

As a rule of thumb, I believe that it should be approx SG = 12 x Evap Area, but it appears to be reading low.

I believe that I have found the cause.

In brief terms, I think that it is a Unit of Measure (UoM) issue. Refer to line 627.

I have assumed that the formula is correct, ie

EvaporationLBpS = boilerKW / (1.055f * steamHeat) - Steamheat - btu/lb converted to kj/kg

However, the issue arises from the fact that metric units are used on RHS and would give a value in kg/s, however the formula is attempting to find a value in lb/s, so hence an additional conversion factor needs to be included, ie 1 kg/s = 2.205 lb/s.

I think that the formula should in fact be:

EvaporationLBpS = (boilerKW / (1.055f * steamHeat) * 2.205f)

This in effect doubles the generation figure. I have "fixed" it in the attached file file and run it to check that it appears more realistic.

I believe that the problem has been generated by mixing imperial and metric UoMs in the file. I feel that there maybe some more problems like this in the file. I would be happy to try and identify them if desired.

Can you please review the proposed changes and if they are correct apply them? Please advise what you think?

Is it possible to be put in touch with the developer who worked on this section as I would like to confirm the formulas with him, so that I can clearly identify the constants and the conversion factors?

Thanks

[cjakeman (cjakeman)]

Hi Peter,

The "Blame" option in SVN tells me that the chunk of code including

  EvaporationLBpS = (boilerKW / (1.055f * steamHeat) * 2.205f)

dates from v550 in Jan 2011 by Doug Jones (dajones) who reads the forum regularly.

Please note there may be other conversion errors in this file, so I would rather check the whole file before committing this patch.

Best wishes,

Chris

[Peter Gulyas (pzgulyas)]

Couldn't this bug be closed? Looks like quite outworn...

[Peter Newell (coals-to-newcastle)]

Hi Peter,

This bug can be closed.

Thanks

Peter

On 6/01/2014 4:06 AM, Peter Gulyas wrote:
> Couldn't this bug be closed? Looks like quite outworn...
>