O2/fuel ratio changes

[Intel55]

Need a lil help on changing the o2/fuel ratio and its impact.

If I go from a o2/fuel ratio of 3.37 down to 2.52 I am lowering flame temperature, lowering the combustion pressure and slowing down the particle velocity? Is that correct?

When calculating the o2/fuel ratio, do you typically include the compressed air along with the o2?

Thanks for any help

[Gordon]

Hi Intel55

What is the fuel and equipment?

[Intel55]

(03-11-2009 06:57 PM)Gordon Wrote:  Hi Intel55

What is the fuel and equipment?

DJ2700. CH4 (nat gas).

[landemarre]

(03-11-2009 07:48 PM)Intel55 Wrote:  

(03-11-2009 06:57 PM)Gordon Wrote:  Hi Intel55

What is the fuel and equipment?

DJ2700. CH4 (nat gas).

Ok I have a good idea about this, I use CH4 on CDS HVOF gun.

stoichiometry at 1 for CH4 is 1 CH4 for 2 O2

In theory, higher temperature is for stoichiometry at 0.9, on CDS it is more near 1.1 or 1.2 probably because this gun have no combustion chamber. If you have less or more than this value, the temperature down. Generally it is better have more O2.

Lower pressure you have slow particles are.

I can't said more.

[Intel55]

(03-12-2009 02:36 PM)landemarre Wrote:  

(03-11-2009 07:48 PM)Intel55 Wrote:  

(03-11-2009 06:57 PM)Gordon Wrote:  Hi Intel55

What is the fuel and equipment?

DJ2700. CH4 (nat gas).

Ok I have a good idea about this, I use CH4 on CDS HVOF gun.

stoichiometry at 1 for CH4 is 1 CH4 for 2 O2

In theory, higher temperature is for stoichiometry at 0.9, on CDS it is more near 1.1 or 1.2 probably because this gun have no combustion chamber. If you have less or more than this value, the temperature down. Generally it is better have more O2.

Lower pressure you have slow particles are.

I can't said more.

Thanks for the info. I am still a lil confused. My Sulzer parameter for 5847 (86/10/4) calls for a o2/fuel ratio of 3.37. I am wondering if I go to a 3.0 or lower and keep the 40 gr/min and 250mm spray distance the same, what effect this will have on the coating. Will the increase of O2 increase flame temperature and particle velocity?

[landemarre]

(03-13-2009 03:53 AM)Intel55 Wrote:  

(03-12-2009 02:36 PM)landemarre Wrote:  

(03-11-2009 07:48 PM)Intel55 Wrote:  

(03-11-2009 06:57 PM)Gordon Wrote:  Hi Intel55

What is the fuel and equipment?

DJ2700. CH4 (nat gas).

Ok I have a good idea about this, I use CH4 on CDS HVOF gun.

stoichiometry at 1 for CH4 is 1 CH4 for 2 O2

In theory, higher temperature is for stoichiometry at 0.9, on CDS it is more near 1.1 or 1.2 probably because this gun have no combustion chamber. If you have less or more than this value, the temperature down. Generally it is better have more O2.

Lower pressure you have slow particles are.

I can't said more.

Thanks for the info. I am still a lil confused. My Sulzer parameter for 5847 (86/10/4) calls for a o2/fuel ratio of 3.37. I am wondering if I go to a 3.0 or lower and keep the 40 gr/min and 250mm spray distance the same, what effect this will have on the coating. Will the increase of O2 increase flame temperature and particle velocity?

You will have flame temperature higher (for the same pressure) so higher temperature particles (or more oxydation) but have same particles velocity (or near the same). So coating should have less unmelt particles or more oxydation, probably more dense and perhaps more strength on it.