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Welcome to the HyRAM discussion forum!  This forum is meant to provide HyRAM users an opportunity to discuss HyRAM with each other and with the HyRAM developers.  Our goal is to facilitate collaboration and help participants find and share questions, answers, example cases, and more. 

The HyRAM software and formal documentation are available at http://hyram.sandia.gov.

 

pratap

Hi,

I am user of HYRAM working in Shell Global Solutions.

I have following questions about your straight and curve flame model.

Straight Flame model:

1 I was looking into technical guide of HyRAM, I see that equations 46-53 is used for the straight flame model (that is the jet flame model without buoyancy correction). There is no indication what expression was used for the transmissivity. Can you confirm whether in that approach whether radiation is based on single point source model or wther it is based on weighted source model.

2) Most of the validations of straight flame model was performed against small scale experiments performed by Schefer et al, can you use this model for large scale jet fires.

Curved Flame Model:

1) How are you calculating X_rad (radiant fraction) in curved flame model, does it use Equation 1 (in Ekoto's paper). But this expression is obtaned by curve fitting some of the small scale experiments performed by Schefer and Molina et al. Therfore, can we use this expression was large scale flames (in Ekoto's experiments).

2) What was the expression used for the flame length which is needed for calculating residence time and radiant fraction? Did you use equation 50 and 51 (technical guide)? But then this expression is obtained by curve fitting small scale experiments. Therefore the question is applicability of that expression for modeling of large scale jet fires.

3)The curve flame model is validated against only two large scale experiments performed by Ekoto et al. How confident are we to claim that curve flame model is better than straight flame model based on just two experimental validations. It is worth keeping in mind that these large scale flames gives us a radiant fraction of 0.141 and 0.167 which is similar to large scale methane flames measured by Lowesmith et al, the reason for this behaviour is attributed to dust particles picked by the flame. This essentially means that we are developing our curved flame model from experiments which shows qualitatively different behaviour than small scale experiments. Any comments on this aspect will be useful.  

Some questions I have is on Ekoto's work (Ekoto et al in IJHE)

1) For the straight flame model, what expression was used for flame length, radiant fraction, whether single point source or weight source model was used for radiation. And whether transmissivity was accounted for. This is not very clear in the publications.

2)
 

Some features
1) Can we get output of calculated notional diameters, visible flame length and radiant fraction. Also it is possible to get distances to different hext flux contours (for example 1.5, 10 and 50 kW/m2).

Please let me know if you have any questions/clarifications.

 

Regards
Pratap