Application of infinite line source and cylindrical‐perfect‐conductors theories to heat pulse measurements with large sensors
Application of infinite line source and cylindrical‐perfect‐conductors theories to heat pulse measurements with large sensors
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DOI：
10.1002/saj2.20250
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发表时间：
2021-03
影响因子：
2.9
通讯作者：
Wei Peng;Yili Lu;T. Ren;R. Horton
中科院分区：
文献类型：
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作者：
Wei Peng;Yili Lu;T. Ren;R. Horton
用热脉冲（HP）传感器测定土壤热特性的无限线源（ILS）理论简单且广泛使用，但忽略了有限的探测半径(r)和热容（Cp）。圆柱完美导体（CPC）理论，通过使用相同圆柱完美导体（ICPC）或不同圆柱完美导体（DCPC）方法来解释randcpp，可以应用于以更高的精度估计土壤热性能值。在本研究中，对ILS和CPC理论进行了评估，并使用不同探针的大型HP传感器进行了数值模拟和实验室测量，对其进行了量化。由有限探针特性引起的误差与饱和度有关：干燥土壤中HP信号的最大温升降低了14%，而潮湿的沙质土壤中只有轻微的温差。有限探针效应对ICPC -和DCPC -热性质值的影响较小，相对误差一般小于5%，但对干燥土壤的相对误差绝对值大于6%。忽略有限探针效应引起的误差随土壤热容(C)与加热探针和传感探针的比值呈线性变化。在本研究中使用的特定传感器，不同探头对HP信号和热性能估计的影响可以忽略不计。在高压传感器的设计中，应考虑有限探头尺寸和性能的影响。CPC理论被推荐用于估算大HP传感器的土壤热特性。
The infinite line source (ILS) theory for soil thermal property determination with heat pulse (HP) sensors is simple and widely‐used, but ignores the finite probe radius (r) and heat capacity (Cp). The cylindrical‐perfect‐conductors (CPC) theory, which accounts forrandCpby using the identical‐cylindrical‐perfect‐conductors (ICPC) or the dissimilar‐cylindrical‐perfect‐conductors (DCPC) approaches, can be applied to estimate soil thermal property values with improved accuracy. In this study, the ILS and CPC theories were evaluated, and the finiterandCpeffects were quantified using numerical simulations and laboratory measurements with a large HP sensor of dissimilar probes. The errors due to finite probe properties were saturation dependent: Dry soils had a 14% reduction in the maximum temperature rise of the HP signal, while only slight temperature differences occurred in wet sandy soils. The finite probe effects were minor on ICPC‐ and DCPC‐thermal property values with relative errors generally less than 5%, but the absolute values of relative errors for dry soils were greater than 6%. Errors caused by ignoring the finite probe effects changed linearly with the ratio of soil heat capacity (C) versusCof the heating and sensing probes. The dissimilar proberhad negligible effect on HP signals and thermal property estimates with the specific sensor used in this study. The effects of finite probe size and properties should be considered in HP sensor design. The CPC theory is recommended for estimating soil thermal properties with large HP sensors.