Shahzeb ， Han Dezhong， Shi Zhongyu， Wu Zhenlong
College of Energy and Power Engineering， Nanjing University of Aeronautics and Astronautics， Nanjing 210016， China
Abstract
Objective The service life and operational reliability of gas turbine engines are severely threatened by various airborne pollutants during flight missions. In complex service environments such as desert dusty areas， rainy weather， and near-water low-altitude flight， solid sand particles and liquid raindrops ingested into the engine can cause severe erosion， abrasion， and corrosion damage to internal components. Therefore， it is essential to install high-efficiency intake dust and water removal devices at the front end of the engine intake channel， among which the inertial particle separator （IPS） has become one of the most widely used and promising pre-separation protective devices due to its simple structure， low flow resistance， and excellent passive separation performance. To clarify the differences in flow field characteristics and phase separation mechanisms of different IPS configurations， this study conducts a comparative numerical analysis of separation efficiencies for solid sand and liquid raindrops across planar and axisymmetric IPS configurations.
Methods In this study， high-fidelity computational fluid dynamics（CFD） simulations based on the k-ω SST turbulence model were adopted to accurately capture complex flow characteristics. Additionally， the discrete phase model （DPM） was coupled to enable two-way coupling between continuous-phase airflow and discrete-phase solid and liquid particles， thereby precisely tracking the motion trajectories， collision behavior，and separation characteristics of particles with different sizes. For particle size settings， the working conditions were divided into two typical categories. A fine particle group with diameters ranging from 1 μm to 15 μm was used to simulate atmospheric suspended fine sand dust， while the large-size liquid droplet group covering 20 μm to 100 μm （including 20， 30， 40， 50， 60， 70， 80， 90， and 100 μm） was set to simulate raindrops under rainy conditions. On this basis， the internal flow field distribution， particle motion behavior， and overall separation efficiency of the two separators were quantitatively analyzed and compared.
Results and Discussion Simulation results indicated that the planar stretched IPS possessed a stable two-dimensional internal flow field. The core channel exhibited uniform velocity distribution and weak secondary flow disturbance， which substantially promoted the inertial separation of microscale solid particles and yielded superior fine sand separation performance. In contrast， the axisymmetric configuration presented typical three-dimensional flow features. Large-scale three-dimensional corner vortices， occupying a spanwise proportion of 14.5%， interfered with the inertial separation process of fine particles and ultimately degraded the fine-particle separation capability. For particles with identical diameters， raindrops had lower density and smaller Stokes numbers， resulting in a 3%~4% lower separation efficiency compared with sand particles.Under large-size raindrop separation conditions， the performance difference between the two configurations was further magnified. The hub of the planar separator generated an ultra-high flow velocity of up to 225 m/s， accompanied by severe local pressure drop and abrupt pressure gradient variations. The increased Weber number induced intense droplet splashing and secondary atomization. Massive fragmented microdroplets escaped with the mainstream airflow， leading to a significant deterioration in water separation efficiency. By comparison， the axisymmetric separator maintained a much milder and more stable internal aerodynamic environment， with a peak hub velocity of only 35 m/s and internal static pressure close to the inlet pressure. Such steady flow conditions effectively suppressed droplet splashing， deformation， and secondary breakup， thereby maintaining the structural integrity of liquid droplets. Consequently， its separation efficiency for large-size raindrops was stably maintained above 80%. These results established that geometric topology fundamentally governed the flow environment and， consequently， the dominant separation physics， with secondary atomization identified as the critical penalty mechanism for liquid contaminants in high-energy IPS designs.
Conclusion In this study， a trade-off is observed between the IPS configuration and the separation mechanism for contaminants in different phases. The planar configuration favors solid particle separation， while the axisymmetric configuration has a significant advantage in liquid raindrop separation.In practical engineering applications， targeted selection of IPS configuration should be conducted according to diverse operating conditions. The planar IPS should be prioritized for desert environments， whereas the axisymmetric IPS is more applicable to rainy and near-water conditions. Optimization of hybrid configurations can be adopted for complex meteorological conditions， enabling full-domain and all-weather flight adaptability of aero-engineintake protection systems.
Keywords： inertial particle separator； planar configuration； axisymmetric configuration； sand particle； raindrop
Get Citation:Shahzeb ， Han Dezhong， Shi Zhongyu， et al. Comparative analysis of separation efficiency forsand particles and raindrops in inertial particle separators［J］. China Powder Science and Technology， 2026， 32（6）： 1-15.
Received:2026-04-27， Revised： 2026-07-02，Online： 2026-08-31。
Funding： The research was supported by the National Natural Science Foundation of China (Grant Nos.12172174, 12572287).
CLC No.:V211.3；TB4
Type Code:A
Serial No.:1008-5548（2026）06-0001-15
