Abstract

A helium flow loop is being assembled at Oak Ridge National Laboratory to analyze heat transfer enhancement for systems such as blanket and divertor components. To efficiently identify optimum geometries for heat transfer enhancement in these applications, simulation work is performed to optimize test section designs that are built and tested in the helium flow loop that operates at 4 MPa and a mass flow rate of 100 g/s. Different ribbed geometries that examine rib shape, rib height, rib orientation, rib spacing, and three-dimensional orientation are modeled and simulated in STAR-CCM+ to compare their ability to remove heat and mitigate pressure drop. Following the simulations, models are selected and manufactured for the helium flow loop tests. Simulations initially focus on a hydrodynamic study to determine the appropriate mesh and physics models and then add a heat flux to analyze the heat transfer abilities of the models. The simulations are run in steady state and use a Reynolds-averaged Navier-Stokes k-ε turbulence model. The helium is modeled as an ideal gas. The simulation explores models of geometries that enhance the heat transfer and decrease pressure drop with an overall goal of increasing fluid collision with the wall. Enhanced geometries are simulated to select appropriate designs for manufacturing, and preliminary experimental results are used to validate the simulations. The factors that are being analyzed in the comparison between the experimental and the simulated results include matching thermocouple temperatures, pressure drop, roughness, and fluid velocity.

摘要

橡树岭国家实验室正在组装一个氦流回路，以分析诸如毯子和偏滤器组件等系统的传热增强。为了在这些应用中有效地确定用于增强传热的最佳几何形状，我们进行了模拟工作以优化在 4 MPa 和 100 g/s 质量流量下运行的氦流回路中构建和测试的测试段设计。在 STAR-CCM+ 中对检查肋条形状、肋条高度、肋条方向、肋条间距和三维方向的不同肋条几何形状进行建模和模拟，以比较它们散热和减轻压降的能力。在模拟之后，为氦流回路测试选择和制造模型。模拟最初侧重于流体动力学研究，以确定适当的网格和物理模型，然后添加热通量来分析模型的传热能力。模拟在稳态下运行并使用雷诺平均 Navier-Stokes k-ε 湍流模型。氦被模拟为理想气体。该模拟探索了几何模型，这些模型可增强传热并降低压降，其总体目标是增加流体与壁的碰撞。模拟增强的几何形状以选择合适的制造设计，并使用初步实验结果来验证模拟。在实验和模拟结果之间的比较中分析的因素包括匹配的热电偶温度、压降、粗糙度和流体速度。