Abstract:

Confronted with low-quality heat source, such as high ash contents, discontinuity and instability in waste heat recovery, innovations are required in the structure of typical heat transfer surface. In this paper a novel structure with rhombus heat transfer surface was presented. This heat transfer surface was efficient in both waste heat recovery and ash blowing. In the heat transfer process, the new heat transfer surface showed similar performance with the staggered tubes arrangement, for instance enhanced heat transfer and relatively large fluid flow resistance and higher convection heat transfer coefficient in the shell side. In the dust blowing process, this surface performed like the aligned tubes arrangement, which was easy to clean and efficient in dust blowing. Numerical simulation and experimental investigation were conducted to obtain heat transfer and flow performance of the new structure. Both numerical and experimental results indicated that the new structure met basic requirements of waste heat recovery, achieving highly efficient heat transfer along with convenience of dust cleaning and descaling.

Key words: heat transfer surface, heat transfer, numerical simulation, experimental validation

摘要：

针对余热利用过程中低温热源的含尘量高、不连续及不稳定等特点, 提出了一种新型菱形受热面结构。在传热过程中, 该受热面表现出管束叉排布置的特征, 传热过能力较强, 流动阻力较大, 壳侧对流换热表面传热系数较高。在实施吹灰过程中, 该受热面呈现出管束顺排布置的特征, 易清洗, 吹灰效率高。采用数值模拟和实验方法研究了新型受热面结构的传热和流动特性, 给出了壳侧的Nusselt数和摩擦因子随Reynolds数的变化规律。实验结果和数值分析均表明, 该受热面能够适应现有余热利用过程的基本要求, 在便于清灰和除垢的同时实现高效传热。

关键词: 受热面, 传热, 数值模拟, 实验验证