CIESC Journal ›› 2023, Vol. 74 ›› Issue (7): 2858-2868.DOI: 10.11949/0438-1157.20230237

• Fluid dynamics and transport phenomena • Previous Articles     Next Articles

Flow process calculation and performance analysis of methane BOG ejector

Chao NIU(), Shengqiang SHEN(), Yan YANG, Bonian PAN, Yiqiao LI   

  1. National Joint Engineering Research Center for Thermal Energy Integration, School of Energy and Power Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China
  • Received:2023-03-14 Revised:2023-07-06 Online:2023-08-31 Published:2023-07-05
  • Contact: Shengqiang SHEN

甲烷BOG喷射器流动过程计算与性能分析

牛超(), 沈胜强(), 杨艳, 潘泊年, 李熠桥   

  1. 大连理工大学能源与动力学院,热能综合利用技术国家地方联合工程研究中心,辽宁 大连 116024
  • 通讯作者: 沈胜强
  • 作者简介:牛超(1998—),男,硕士,niuchao1@mail.dlut.edu.cn
  • 基金资助:
    国家自然科学基金重点项目(51936002)

Abstract:

The introduction of ejectors in the boil-off gas (BOG) reliquefaction system in a liquefied natural gas (LNG) carrier can save energy and improve system operating efficiency. Due to the special storage condition of LNG, it is important to design a high-performance ejector. The structural design calculation of methane BOG ejector under giving operating condition was carried out by using the gas dynamic method. Based on the Mixture multiphase flow model and SST k-ω turbulence model, a numerical model of methane BOG ejector was established. The effect of operating conditions and structural parameters on the entrainment performance of methane BOG ejector was calculated and analyzed. The results showed that for the ejector with a fixed structure, there is an optimal motive pressure for the entrainment ratio to reach the maximum. Increasing the induced pressure can always improve the entrainment ratio. Under giving design operating conditions, keeping other structural parameters fixed, the energy losses caused by shock waves and vortices inside the ejector is the lowest and the entrainment ratio reaches a maximum when the primary nozzle outlet diameter and primary nozzle outlet position are 9.6 mm and 41 mm, respectively.

Key words: methane ejector, BOG re-liquefaction, entrainment ratio, CFD, two-phase flow

摘要:

在液化天然气(LNG)运输船中的蒸发气(BOG)再液化系统中引入喷射器可以节约能源,提高系统工作效率。由于LNG的存储工况较为严苛,设计高性能的喷射器至关重要。采用气体动力学函数法对给定工况下的甲烷BOG喷射器进行了结构设计。基于Mixture多相流模型和SST k-ω湍流模型建立了甲烷BOG喷射器数值计算模型,计算分析了运行参数和结构参数对甲烷BOG喷射器引射性能的影响规律。研究结果表明,对于固定结构的甲烷BOG喷射器,存在最佳工作压力使引射比达到最大值,提升引射压力可以持续提高引射比。在设计工况下,保持其他结构参数不变,当主喷嘴出口直径和主喷嘴出口位置分别为9.6 mm和41 mm时,喷射器内部由激波和涡流造成的能量损失最小,引射比达到最大值。

关键词: 甲烷喷射器, BOG再液化, 引射比, 计算流体力学, 两相流

CLC Number: