Burluka, A. A., et al. Fuel, 2017, 189, 66-78.
Combustion velocities of premixed hydrogen-air, n-hexane-air and n-octane-air fires were measured and compared to those of deuterium-air, n-hexane-d14-air and n-octane-air with identical initial conditions. These are compared outputs as follows:
When deuterium atoms were replaced by hydrogen atoms in n-hexane (n-hexane-d14) and n-octane (n-octane-d18), the calculated laminar combustion velocity fell about 20%. The average laminar combustion rates of normal and deuterated n-hexane and n-octane are different, because the hydrogen atoms have higher thermal diffusivity and reactivity than the deuterium atoms.
Deuterium was measured to burn about 30% slower than hydrogen over the range of equivalence ratios explored. Under turbulent flow, the effect of isotopes on combustion rates is significantly reduced. Comparing n-hexane and n-octane and deuterated n-hexane (n-hexane-d14) and deuterated n-octane (n-octane-d18) burning rates, deuterated alkanes burning 8 % slower than ordinary alkanes.
The differences between the H air flame burning rate and D air flame burn rate under turbulent flow are reduced by a fifth from the results with laminar flow. All of this shows that turbulent diffusivity enhances transport in turbulent combustion and has greater control over kinetic isotope effects.
