Like I said before I'm not saying that you shouldn't challenge yourself.
I encourage you to do so and I do it myself also at some times. But a photo is still just a combination of exposure time (shutter speed), amount of light (aperture) and light sensitivity (ISO). These three work in a triangle and to get the right exposure you have to deal with these three items. There is nothing you can change about that. And you can experiment all you want, if you want a certain result there are some "rules" for some situations.
In this case, smoke photography, is one of these rules that you have to use a fast shutter speed with lots of light. The shutter speed "part of the rule" is fixed. A too long shutter speed causes movement in the smoke, so shutter speed should be fast! The next thing is the amount of light or the light sensitivity.
You can try to catch lots of light on your sensor by using a big aperture (smaller f-number), but that also causes a smaller depth of field. At f/1.8 with your 35mm lens the total amount of depth of field is 0.15cm (= 0.00492125984 feet (1⁄16 inch)) (calculated with:
Online Depth of Field Calculator). 0.15cm is far not enough to get the smoke sharp. I see you're using a D750, which is a FX camera. FX camera's even have a smaller DOF.
So the next thing is raising the ISO. At ISO 640 the noise should still be reasonable, but at higher ISO's the noise will be more and more present. You don't want that. Definitely not with smoke pictures, because you want that pictures to be as clean as possible.
So you have 2 problems. You can't open up the aperture because of depth of field and you can't raise the ISO because of noise.
Solution? Using a flash!
With the flash you can use a very fast shutter speed, close down the aperture to create more depth of field to get all the smoke inside the sharp area and lower the ISO to suppress noise. This kind of picture should be taken with ISO 100/200.
Finally:
Challenging yourself isn't a bad thing. Without challenging yourself you'll never meet your own or your camera's boundaries. But be reasonable and know the limits. And with this experiment the limits are what I've written down.