The evolution of particle size distribution (PSD) of fine polydisperse particles at high number concentrations (>10⁵ cm⁻³) was simulated through a combined model employing direct quadrature method of moments (DQMOM) with heat and mass transfer equations. The PSD was assumed to retain log-normal distribution during the heterogeneous condensation process. The model was first verified by exact solution and experimental data prior to investigating the influence of initial conditions on final PSD under an octadecane–nitrogen atmosphere. Low particle number concentrations and high vapor concentrations were beneficial to shift the PSD to larger particles having a narrower distribution. Additionally, vapor depletion has more influence on the final PSD than the heat release parameter for a number concentration of 10⁶ cm⁻³. This study may assist the design process of a gas–solid separating cyclone, to eliminate dust from high-temperature volatiles by pyrolysis of solid fuels.

高数浓度（> 10 ⁵  cm ^-3）下的精细多分散颗粒的粒径分布（PSD）的演变）是通过使用热矩和传质方程的矩量直接正交方法（DQMOM）的组合模型进行模拟的。假设PSD在非均相冷凝过程中保持对数正态分布。在研究初始条件对十八烷-氮气氛下初始PSD对最终PSD的影响之前，首先通过精确解和实验数据验证了该模型。低颗粒数浓度和高蒸气浓度有利于将PSD转变为分布较窄的较大颗粒。另外，对于10 ⁶  cm ^-3的数浓度，蒸气耗散对最终PSD的影响比放热参数的影响更大。这项研究可能有助于气固分离旋风分离器的设计过程，以通过固体燃料的热解消除高温挥发物中的粉尘。