Heat flux

[kingdal]

Hi all

Ever since I started building coils, I've always built to certain resistances. Wire gauge was something I used to control the number of wraps and the size of the coil. The other day I saw on the Steam engine calculator that different gauges and resistances affect something called heat flux.

Can someone explain, in plain English, what this is in relation to vaping? I know heat flux isnt the same as temperature but If the dna 40 uses temperature control to control quality of the flavor, should I be building my coils to certain heat flux measurements?

Little confused here. Thanks!

 

[Circa Survivor]

.....I dunno lol (I know, I'm not helping xD)

 

[State O' Flux]

Heat flux is in reference to the "balancing act" between wire gauge/length, physical wrap count/coil ID that will actually fit in the atomizer and coil temperature per wattage applied... in this instance, radiant heat is expressed in milliwatts divided by square millimeters of surface area, or mW/mm².

"Dampmaskin" (Steam Engine) uses an optimal color code range to indicate that all your variables are in balance, and will deliver good performance... in simple terms, a vape heat range that suits your subjective tastes.

For example... using a DC RDA, a dual parallel build using 112mm of 25 gauge Kanthal A1, with coil(s) dimensions of 2.5mm ID and an 11/10 wrap count (2mm tails) providing a net resistance of 0.5Ω.
The color code indicates that 56 watts will provide an approximate median of 175 mW/mm² (green zone) temperature. If you want a cooler or warmer vape, adjust wattage accordingly.

To come at it from another direction... Lets say you have a 100 watt peak output. What would be a good wire size to build a very warm vaping DC RDA?
24 gauge wire, with coil(s) dimensions of 2.5mm ID and an 8/7 wrap count providing a net resistance of 0.3Ω, will produce 368 mW/mm² (well into the red, or hotter vape zone) when 100 watts is applied.

You can tweak this from any number of directions. From the perspective of a mech mod user, to obtain peak performance with the batteries and wire gauges you have on hand... to the perspective of someone who just bought a 200 watt APV. ;-)

 

[readeuler]

My understanding is that it's a measure of how concentrated the heat is - it tells you how much heat will radiated from a small 'unit' of coil surface area. Take-away: It's really just a ratio of wattage to coil surface area.

You can see for yourself, using Steam-Engine: Whether you're using 10.23 wraps of 30ga Kanthal A1 around a 1.3mm bit (1.8 ohms, the default) or using 10.23 wraps of Nichrome 60 (1.378 ohms), both at 10 watts, the heat flux is identical: The surface areas and wattages are identical, thus the heat flux is as well.

Build 1
Build 2

It's a function of both coil geometry (surface area: wire gauge and length of wire used) and total wattage applied. At the same wattage, more surface area (thicker wire or a longer piece) will decrease the flux, leading to overall cooler vapor at the time of vaporization (the RDA itself can be extremely hot if you've got a lot of 24ga wire with low heat flux; there's a lot of heat transfer happening overall. But at each tiny spot of vaporization, there isn't a lot of energy exchange).

Personally, I never pay too much attention, but I'm also not an expert. Mostly because I'm never quite sure how much wattage I'm getting, but also because I suspect that the temperature of your inhale depends pretty significantly on things other than heat flux (total wire mass, airflow, wicking, etc). That's not to say it's not good to know, I've just never used it much. But you could, ideally, use it to get an idea of how warm the vapor will be at a certain wattage.

 

[nasca]

I dont understand it, either. But if I aim for somewhere between 200 and 260, I'm good.

 

[kingdal]

Heat flux is in reference to the "balancing act" between wire gauge/length, physical wrap count/coil ID that will actually fit in the atomizer and coil temperature per wattage applied... in this instance, radiant heat is expressed in milliwatts divided by square millimeters of surface area, or mW/mm².

"Dampmaskin" (Steam Engine) uses an optimal color code range to indicate that all your variables are in balance, and will deliver good performance... in simple terms, a vape heat range that suits your subjective tastes.

For example... using a DC RDA, a dual parallel build using 112mm of 25 gauge Kanthal A1, with coil(s) dimensions of 2.5mm ID and an 11/10 wrap count (2mm tails) providing a net resistance of 0.5Ω.
The color code indicates that 56 watts will provide an approximate median of 175 mW/mm² (green zone) temperature. If you want a cooler or warmer vape, adjust wattage accordingly.

To come at it from another direction... Lets say you have a 100 watt peak output. What would be a good wire size to build a very warm vaping DC RDA?
24 gauge wire, with coil(s) dimensions of 2.5mm ID and an 8/7 wrap count providing a net resistance of 0.3Ω, will produce 368 mW/mm² (well into the red, or hotter vape zone) when 100 watts is applied.

You can tweak this from any number of directions. From the perspective of a mech mod user, to obtain peak performance with the batteries and wire gauges you have on hand... to the perspective of someone who just bought a 200 watt APV. ;-)

You lost me on the first part but I get the second (and most useful) part. Thank you!