Daniel Medeiros

https://en.wikipedia.org/wiki/Millisecond

maybe it is because this function has two variations and python only sees the one where the first argument is the compound index. also be careful to not misunderstand mass/molar and flow/fraction.

try using oms1.SetOverallCompoundMolarFlow('Methane', methane_molar_flow)

https://github.com/DanWBR/dwsim/blob/windows/DWSIM.UnitOperations/UnitOperations/Pipe.vb#L624

yes => https://github.com/DanWBR/dwsim/blob/windows/DWSIM.UnitOperations/UnitOperations/Pipe.vb#L1083 old code in Portuguese, sorry.

all accessories are converted to an equivalent length of straight tube, then the pressure drop can be calculated.

what are the combustion reactions for them?

This is the calculation procedure: https://github.com/DanWBR/dwsim/blob/windows/DWSIM.Plugins.HeatOfCombustion/Form1.vb#L44 It takes into account the combustion of hydrocarbons only. Maybe you can help me to spot the error.