Journal of Yangtze River Scientific Research Institute ›› 2023, Vol. 40 ›› Issue (8): 157-162.DOI: 10.11988/ckyyb.20220259

• Hydraulic Structure and Material • Previous Articles     Next Articles

Thermal Conductivity Model for Polyurethane Insulation Material in Consideration of Moisture

WANG Hou-mi1, LIU Chao1, MING Feng2,3   

  1. 1. CCCC-SHB Fourth Engineering Co. Ltd., Luoyang 471013, China;
    2. Qinghai Communication Holding Construction Engineering Group Co., Ltd., Xining 810003, China;
    3. State Key Laboratory of Frozen Soil Engineering, Northwest Institute of Eco-environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China
  • Received:2022-03-17 Revised:2022-05-30 Online:2023-08-01 Published:2023-08-09

Abstract: Laying insulation materials is an effective measure to mitigate the freezing damage to channels. However, the absorption of moisture by insulation materials can lead to a deterioration in their thermal insulation performance. To investigate the impact of moisture content on thermal conductivity of insulation materials, a model predicting thermal conductivity taking moisture content into account was established using the homogenization method based on the minimum thermal resistance law. Furthermore, the influence of porosity and moisture content on thermal conductivity was examined. The proposed model was then validated against experimental results and an existing model. The findings reveal that thermal conductivity decreases with the increase of porosity, but increases with the increase of moisture content. The error between the predicted and measured results is less than 5%, thereby confirming the feasibility of the proposed model in calculating the thermal conductivity of insulation materials. Additionally, moisture is identified as a significant factor in diminishing the thermal insulation performance of polyurethane rigid foam. Consequently, enhancing the hydrophobic properties of insulation materials holds great practical significance in improving its thermal insulation performance. Several suggestions are put forward to enhance the hydrophobicity of polyurethane insulation materials.

Key words: canal, insulation material, thermal conductivity, polyurethane, prediction model

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