### A development of particle-based Eulerian property index (EPI) and an analysis of water droplet particles with phase change

- 주제어 (키워드) Particle property index , Eulerian , Swirling pipe , Cyclone separator , Cooling tower , Lagrangian , Water droplet , Phase change
- 발행기관 서강대학교 일반대학원
- 지도교수 강성원
- 발행년도 2022
- 학위수여년월 2022. 2
- 학위명 석사
- 학과 및 전공 일반대학원 기계공학과
- 실제 URI http://www.dcollection.net/handler/sogang/000000066544
- UCI I804:11029-000000066544
- 본문언어 영어
- 저작권 서강대학교 논문은 저작권 보호를 받습니다.

#### 초록 (요약문)

The Lagrangian approach is mostly used to analyze particle-laden flow characteristics. The complexity and high computational cost are the drawbacks associated with the Lagrangian approach, in order to avoid this Eulerian approach is used as an alternative technique for the dispersed phase. The objective of the present study is to develop Eulerian indices to observe fluid flow characteristics laden with particles. The developed Eulerian indices such as residence time, travel distance, mean centrifugal force is evaluated for particle-based fluid flow, in the cylinder for swirling motion and cooling tower natural draft. The Eulerian property indices are computed with different droplet diameter cases and results are compared with Lagrangian property indices. The flow characteristics in cyclone separators are analyzed by using these developed indices. The effect of inlet velocity and vortex finder length in cyclone separator is observed for the tangential velocity, mean centrifugal force and separation efficiency. When performing an analysis of particle simulation, it is important to perform statistical analysis based on modeling such as particle diameter distribution in order to obtain more realistic analysis. However, using particle diameter distribution modeling is difficult thing associated with the Eulerian approach, because it requires very complex modeling to use particle diameter distribution. For this reason, Lagrangian approach is used as an alternative technique for dispersed phase. As a result, statistical prediction and flow field analysis were performed based on Lagrangian droplet particles with phase change from a cooling tower under a background air flow. Statistical tendency of the particle temperature and diameter were investigated for Lagrangian water droplets according to the background air temperature and gravitational effects. As the particle diameter distribution model, the Rosin-Rammler distribution was used for about 2.5 million droplets particles. The horseshoe vortices were observed behind the cooling tower, which affects especially small droplets by increasing condensation via enhanced mixing with a cold background air. It was observed that the gravity effect increases the strength of the horseshoe vortices.

more