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Predicted effects of soil dry density and initial water content on performance of a heat exchanger buried in an unsaturated Loess Parent material.

机译：土壤干密度和初始含水量对埋在非饱和黄土母体材料中的热交换器性能的预测影响。

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The influence of dry density and soil water content on the performance of a heat exchanger buried in a Loess Parent material was studied for heat rejection to the soil. A mathematical model was developed to predict heat exchanger performance based on partial differential equations for coupled heat and water flow. Soil properties in the analysis included thermal conductivity and matric potential, measured in the laboratory, and unsaturated hydraulic conductivity and water vapor diffusion coefficients, derived according to methods in the literature. In addition, the effect of thermal contact conductance between the heat exchanger and adjacent soil was considered. A lumped model for predicting reduction of thermal contact conductance at the exchanger-soil interface was incorporated into the model which was based on soil shrinkage and air-gap thermal contact conductance data obtained in the laboratory.;Heat exchanger performance was predicted for three assumed heat and water flow cases; constant soil properties, thermally-induced water flow and thermally-induced water flow with thermal contact conductance. Results of the mathematical modeling efforts neglecting thermal contact conductance indicated that increasing dry density had a substantial impact on heat exchanger performance when thermally-induced liquid and vapor phase water was considered. For an initial water content of 0.16 Mg/Mg dry basis, increasing dry density from 1.40 to 1.60 Mg/m

机译：研究了干密度和土壤含水量对埋在黄土母体材料中的换热器性能的影响，以排除土壤中的热量。开发了一个数学模型，用于基于热和水耦合流动的偏微分方程来预测热交换器的性能。分析中的土壤特性包括在实验室中测得的热导率和基体电势，以及根据文献方法得出的不饱和水力传导率和水蒸气扩散系数。另外，还考虑了热交换器和邻近土壤之间的热接触传导的影响。基于土壤收缩率和实验室获得的气隙热接触电导数据，将一个用于预测交换器-土壤界面热接触电导率降低的集总模型纳入模型;预测了三个假定热量的热交换性能和水流箱；恒定的土壤特性，热诱导的水流和具有热接触电导的热诱导的水流。忽略热接触电导的数学建模工作的结果表明，当考虑热诱导的液相和气相水时，增加的干密度对热交换器的性能有重大影响。对于初始含水量为0.16 Mg / Mg干基，将干密度从1.40 Mg / m增加到1.60 Mg / m

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作者
Remund, Charles Paul.;
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The University of Nebraska - Lincoln.;

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授予单位 The University of Nebraska - Lincoln.;
学科 Engineering Agricultural.;Engineering Mechanical.
学位 Ph.D.
年度 1988
页码 343 p.
总页数 343
原文格式 PDF
正文语种 eng
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4. Unsaturated soil mechanics and implications for clayey soils compacted dry of standard optimum water content [C] . G. J. Burton, J. N. Anderson Ground engineering in a changing world . 2012

机译：非饱和土壤力学及其对黏土干燥的最佳标准含水量的影响
5. Determining the relative effects of volumetric water content and dry density on the dielectric constant of soils [D] . Rasch, Shane M. 2011

机译：确定体积含水量和干密度对土壤介电常数的相对影响
6. Projected soil organic carbon loss in response to climate warming and soil water content in a loess watershed [O] . Fubo Zhao, Yiping Wu, Jinyu Hui, 2021

机译：投影土壤有机碳损失以应对黄土水域的气候变暖和土壤水含量
7. This article presents a new numerical model describing the behaviour of a thermally thick wood sample exposed to high solar heat flux (above 1 MW/m2). A preliminary study based on dimensionless numbers is used to classify the problem and support model building assumptions. Then, a model based on mass, momentum and energy balance equations is proposed. These equations are coupled with liquid-vapour drying model and pseudo species biomass degradation model. By comparing to a former experimental study, preliminary results have shown that these equations are not enough to accurately predict biomass behaviour under high solar heat flux. Indeed, a char layer acting as radiative shield forms on the sample exposed surface. In addition to this classical set of equations, it is mandatory to take into account radiation penetration into the medium. Furthermore, as biomass contains water, medium deformation consecutively to char steam gasification must also be implemented. Finally, with the addition of these two strategies, the model is able to properly capture the degradation of biomass when exposed to high radiative heat flux over a range of sample initial moisture content. Additional insights of biomass behaviour under high solar heat flux were also derived. Drying, pyrolysis and gasification fronts are present at the same time inside of the sample. The coexistence of these three thermochemical fronts leads to char gasification by the steam produced from drying of the sample, which it is the main phenomenon behind medium ablation. [O] . Pozzobon, Victor, Salvador, Sylvain, Bézian, Jean Jacques 2018

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8. Investigation of Combined Heat and Mass Transfer from a Wet Heat Exchanger. Part 1. Formulation of an Approximate Heat/Mass Transfer Model for Calculating the Performance of Heat Exchangers in Dry/Wet Operation [R] . Kreid, D. K., Hauser, S. G., Johnson, B. M. 1982

机译：湿式换热器的传热传质研究。第1部分：用于计算干/湿操作中换热器性能的近似传热传质模型的公式

Predicted effects of soil dry density and initial water content on performance of a heat exchanger buried in an unsaturated Loess Parent material.

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