An Experimental and Numerical Investigation of Turbulent Variable Fluid Property Heat Transfer and Fluid Flow in Enhanced Tubes

强化管内湍流变流体性质传热和流体流动的实验与数值研究

• 批准号: 9412596
• 负责人: Michael Jensen
• 金额: $ 25.6万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-10-01 至 1999-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9412596&HistoricalAwards=false
• 关键词: Experimental; Numerical; Investigation; Turbulent; Variable

The proposed research will investigate both experimentally and numerically turbulent heat transfer and pressure drop in internally-finned tubes when there are large variable fluid property effects. The internally-finned tube geometry is ideal to test modeling capabilities because they are industrially relevant, have much surface area, have complex hydrodynamics due to the geometry, are amenable to numerical modeling, and are experimentally testable in a lab over a wide range of geometric and operating conditions. Ten internally-finned tubes are available for testing the experimental investigation; these tubes cover a wide range of geometric parameters. The tube will be tested in both heating and cooling over a range of wall-to-bulk temperature differences. The working fluids will be water, ethylene glycol, and mineral oil. In the numerical modeling, primary emphasis will be placed on development of appropriate near-wall modeling and accommodation of variable fluid properties. A newly developed anisotropic turbulence model, called the vorticity flux model, will be extended for use in this project and applied to both axially and spirally finned tubes where anisotropic turbulence is important. The numerical model will be validated by comparison against detailed local and overall data from the literature, and new overall data from this investigation. The validated model will fully describe the governing mechanisms for heat transfer and pressure drop in this geometry (particularly the effects of fin geometry and helix angle). It also will provide guidance on the incorporation of variable fluid properties in numerical models and with enhanced heat transfer techniques and suggest appropriate methods for the development of physically-based correlations for Nusselt numbers and friction factors.

本研究以实验与数值模拟相结合的方式，探讨内鳍管在流体物性变化较大时之紊流热传与压力降。内翅片管几何形状是测试建模能力的理想选择，因为它们与工业相关，具有很大的表面积，由于几何形状而具有复杂的流体动力学，易于进行数值建模，并且在实验室中可以在广泛的几何和操作条件下进行实验测试。 十个内翅片管可用于测试实验研究;这些管涵盖了广泛的几何参数。该管将在一系列壁体温差下进行加热和冷却试验。工作流体将是水、乙二醇和矿物油。在数值模拟中，主要重点将放在发展适当的近壁建模和适应可变的流体特性。一个新开发的各向异性湍流模型，称为涡通量模型，将被扩展用于本项目中，并适用于轴向和双翅片管，其中各向异性湍流是重要的。将通过与文献中的详细局部和总体数据以及本研究中的新总体数据进行比较，对数值模型进行验证。经验证的模型将充分描述这种几何形状下的传热和压降的控制机制（特别是翅片几何形状和螺旋角的影响）。它还将提供指导，在数值模型中的可变流体特性的结合，并与增强传热技术，并建议适当的方法为基础的努塞尔数和摩擦系数的物理相关性的发展。