2 replies to this topic

[zdendacejka]

Hi,
I'm revising and reimplementing software for modelling effects of hazardous substances releases. I got to the area gas jet dispersion (also named as turbulent jets, sonic and subsonic gas jets etc.) For the kick off I've tried to find some semi-empirical models and I got to the chapter 15.20 - Dispersion of Jets and Plumes in that "gnarly" bible - Lee's Loss Prevention In Process Industries... and I'm really confused, lot of contradictions!

In part 15.20.2 - Gas jets there are several statements, for example:

• equation 15.20.8 (simplified)
• equation 15.20.18

Where c(x) means volumetric concentration at distance x (on the axis), ro is density, o means orifice, d is diameter of the hole (orifice) and k is constant (usually 5 - 6).

Can you see that disproportion of density ratios? Which form is the right one? Are there any correct equations for estimating concentration profile during gas jet (semi-empirical, not CFD)?

Thanks for your advices.

[mbeychok]

zdendacejka:

I think you would find it very useful to read this article in the online Citizendium encylopedia:

Accidental release source terms

[zdendacejka]

zdendacejka:

I think you would find it very useful to read this article in the online Citizendium encylopedia:

Accidental release source terms

Thanks, but this is not exactly what I need. Referenced article deals with source term problems - releases, mass flow calculation, evaporation etc. But I solve a subsequent problem - dispersion.

Suppose I've calculated relevant parameters of outflow (critical) through hole - density, velocity, mass flow in hole. Because of high outflow velocity (in fact high Reynolds number) I can't use PLUME model for subsequent dispersion. High momentum of outflowing gas causes dilution and other behavior... I have to use jet model - and that is the critical point, which one of jet models mentioned above is the correct one?