In most simulations of fine particles in reacting flows, including sooting flames, enthalpy exchanges between gas and particle phases and differential diffusion between the two phases can be neglected, since the particle mass fraction is generally very small. However, when the nanoparticles mass fraction is very large representing up to 50% of the mixture mass, the conservation of the total enthalpy and/or the total mass becomes critical. In the present paper, we investigate the impact of mass and enthalpy conservation in the modelling of titania nanoparticles synthesis in flames, classically characterised by a high conversation rate and consequently a high nanoparticles concentration. It is shown that when the nanoparticles concentration is high, neglecting the enthalpy of the particle phase may lead to almost 70% relative error on the temperature profile and to relative errors on the main titania species mass fractions and combustion products ranging from 20% to 100%. It is also established that neglecting the differential diffusion of the gas phase with respect to the particle phase is also significant, with almost 15% relative error on the TiO${}_2$ mole fraction, although the effect on combustion products is minor.

在大多数模拟反应流中的细颗粒（包括烟尘）中，由于颗粒质量分数通常很小，因此可以忽略气相和颗粒相之间的焓交换以及两相之间的差异扩散。然而，当纳米颗粒的质量分数非常大，代表高达混合物质量的50％时，总焓和/或总质量的守恒变得至关重要。在本文中，我们研究了质量和焓守恒在火焰中二氧化钛纳米粒子合成模型中的影响，其经典特征是高对话速率并因此具有高纳米粒子浓度。结果表明，当纳米颗粒浓度较高时，忽略颗粒相的焓可能导致温度曲线上的相对误差接近70％，以及主要的二氧化钛物质质量分数和燃烧产物的相对误差在20％至100％的范围内。还可以确定，忽略气相相对于颗粒相的差异扩散也很重要，TiO的相对误差几乎为15％${}_{\mathrm{2个}}$ 摩尔分数，尽管对燃烧产物的影响很小。