地下换热管土结构冻胀变形模拟

以地源热泵技术在农业节能领域中的应用为研究背景,针对地下换热管土结构冻胀变形问题开展数值模拟研究,基于孔隙增长率函数、冻土本构方程、含水量方程和相变传热理论建立数值模型,并结合试验验证该模型的有效性。利用模型对冻胀过程中岩土应力和管体变形特性进行分析,并考察管体降温速率（0.1、0.2、0.3℃/h）对上述2方面的影响。结果表明,岩土冻胀应力和管体变形程度均随冻结范围增大而增大,当冻结直径达到365 mm时,进水管流通面积减小约3.5%,出水管流通面积减小可超过4%,可见出水管的变形更为明显;冻结范围基本一致的情况下,换热管体缓慢降温可导致较大的岩土冻胀应力和出水管变形。...

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Bibliographic Details
Published in农业工程学报 Vol. 32; no. 18; pp. 118 - 124
Main Author 白莉 王有镗 高青 江彦 李兆强
Format Journal Article
LanguageChinese
Published 吉林建筑大学市政与环境工程学院,长春,130118%山东理工大学建筑工程学院,淄博,255049%吉林大学热能工程系,长春,130025%吉林医药食品工程有限公司,长春,130021 2016
Subjects
冻胀
变形
岩土应力
热泵系统
管体
管土结构
变形
热泵系统
heat pump systems
soil stress
pipe-soil structure
管土结构
deformation
pipe
frost heave
岩土应力
管体
冻胀
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ISSN1002-6819
DOI10.11975/j.issn.1002-6819.2016.18.016

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Summary:以地源热泵技术在农业节能领域中的应用为研究背景,针对地下换热管土结构冻胀变形问题开展数值模拟研究,基于孔隙增长率函数、冻土本构方程、含水量方程和相变传热理论建立数值模型,并结合试验验证该模型的有效性。利用模型对冻胀过程中岩土应力和管体变形特性进行分析,并考察管体降温速率（0.1、0.2、0.3℃/h）对上述2方面的影响。结果表明,岩土冻胀应力和管体变形程度均随冻结范围增大而增大,当冻结直径达到365 mm时,进水管流通面积减小约3.5%,出水管流通面积减小可超过4%,可见出水管的变形更为明显;冻结范围基本一致的情况下,换热管体缓慢降温可导致较大的岩土冻胀应力和出水管变形。
Bibliography:11-2047/S
The research background of this paper is the ground source heat pump（GSHP） technology applied in the field of agriculture energy conservation. The typical application is the GSHP used in greenhouse. However, the operating temperature of ground heat exchange pipe usually sustains below 0°C, when the GSHP runs during the winter night in cold regions. The sustaining low temperature can lead to pore water freeze and volume expansion in soil, which is called frost heave. In this paper, numerical simulation study was conducted to investigate the deformation of pipe-soil heat exchange structure due to frost heave. The numerical model, on the basis of porosity rate function, frozen soil constitutive equation, water content equation and phase change heat transfer theory, was built on the simulation platform ABAQUS and thermal-mechanical coupled subroutine compiled in Fortran. The semicircle soil computational domain and U-pipe were adopted in 2-D geometrical model. Based on the assumptions of this model, its
ISSN:1002-6819
DOI:10.11975/j.issn.1002-6819.2016.18.016