饱和—非饱和区热迁移特性的试验研究
发布时间：2018-12-15 04:03
【摘要】：人类社会的发展与进步离不开能源,能源开发利用技术的不断进步推动了经济的发展和科学的进步。目前,对新能源的开发与利用是当今世界发展的主题之一。浅层地温能作为一种积蓄在地下(0~200m)的优质清洁能源,因其具有分布广泛、储量巨大、埋藏较浅、可就近开发利用等优点被世界各国青睐。土壤源热泵作为一种节能、环保的热泵技术,其地埋管换热器与周围土壤间的热交换能力一直是广大科技工作者关注的重点。地埋管埋设于饱和带与非饱和带中,热交换以非稳态的方式进行,过程十分复杂。在非饱和带中,热交换介质涉及固、液、气三相,传热方式主要为热传导;在饱和带中,热交换在固、液两相间进行,传热方式包括热传导与热对流。本文根据多孔介质传热传质理论和地埋管换热器周围土壤的实际情况,搭建了砂箱试验台,对无渗流、不同渗流速度、不同冷/热源温度、不同环境温度条件下饱和-非饱和区的热迁移特性进行了研究。在研究过程中,将灰色马尔科夫模型应用于对热迁移趋势性和随机性规律的研究当中。结果表明,饱和、非饱和区的热迁移特性不尽相同。无渗流、不同渗流速度、不同冷/热源温度、不同环境温度对饱和-非饱和区的热迁移有着不同的影响。无渗流条件下,饱和区热量由热源向外传递,关于热源对称;非饱和区热迁移特性与饱和区相似,无明显差别。随机温度值在1℃之内。饱和区中随机状态集中于中等级别,非饱和区随机状态分布均匀。有渗流条件下,热迁移强于无渗流条件下热迁移,饱和区强于非饱和区,饱和区部分热量向非饱和区迁移;随着渗流速度的增加,热迁移逐渐增强,饱和区与非饱和区差别减小。受渗流作用的影响,U型管下游随机温度增大,部分区域随机温度大于1℃。饱和区中随机状态集中于中等级别,非饱和区随机状态分布均匀。冷、热源温度决定了饱和-非饱和区热迁移的程度与方向,饱和区热迁移强于非饱和区。同等条件下,热迁移在加热条件优于制冷条件。环境温度变化对饱和区与非饱和区影响不同。非饱和区中,环境温度变化主要影响热迁移的趋势性;饱和区中,环境温度的变化主要影响热迁移的随机性。
[Abstract]:The development and progress of human society can not be separated from energy, and the continuous progress of energy development and utilization technology has promoted the economic development and scientific progress. At present, the development and utilization of new energy is one of the themes of the development of the world. Shallow geothermal energy, as a kind of high-quality clean energy stored underground (0 ~ 200m), has been favored by countries all over the world for its advantages of wide distribution, huge reserves, shallow burial, and the ability to be developed and utilized nearby. Ground-source heat pump (GSHP) is an energy-saving and environment-friendly heat pump technology. The heat exchange capacity between ground heat exchanger and surrounding soil is always the focus of scientific and technological workers. The buried pipe is buried in the saturated zone and unsaturated zone, and the heat exchange takes place in an unsteady state, and the process is very complicated. In the unsaturated zone, the heat exchange medium involves solid, liquid and gas, and the heat transfer mode is mainly heat conduction; in the saturated zone, the heat exchange takes place between solid and liquid phases, and the heat transfer mode includes heat conduction and heat convection. Based on the theory of heat and mass transfer in porous media and the actual situation of soil around the ground buried tube heat exchanger, a sand box test bed is built. The thermal transport characteristics of saturated-unsaturated region at different ambient temperatures were investigated. In the process of research, grey Markov model is applied to study the trend and randomness of heat transfer. The results show that the heat transfer characteristics of saturated and unsaturated regions are different. No seepage, different seepage velocity, different cold / heat source temperature, different ambient temperature have different effects on the heat transfer in saturated-unsaturated region. Under the condition of no seepage, the heat in the saturated region is transferred from the heat source to the external heat source, and the heat transfer characteristics in the unsaturated region are similar to those in the saturated region, but there is no obvious difference. The random temperature is within 1 鈩，
本文编号：2379935
[Abstract]:The development and progress of human society can not be separated from energy, and the continuous progress of energy development and utilization technology has promoted the economic development and scientific progress. At present, the development and utilization of new energy is one of the themes of the development of the world. Shallow geothermal energy, as a kind of high-quality clean energy stored underground (0 ~ 200m), has been favored by countries all over the world for its advantages of wide distribution, huge reserves, shallow burial, and the ability to be developed and utilized nearby. Ground-source heat pump (GSHP) is an energy-saving and environment-friendly heat pump technology. The heat exchange capacity between ground heat exchanger and surrounding soil is always the focus of scientific and technological workers. The buried pipe is buried in the saturated zone and unsaturated zone, and the heat exchange takes place in an unsteady state, and the process is very complicated. In the unsaturated zone, the heat exchange medium involves solid, liquid and gas, and the heat transfer mode is mainly heat conduction; in the saturated zone, the heat exchange takes place between solid and liquid phases, and the heat transfer mode includes heat conduction and heat convection. Based on the theory of heat and mass transfer in porous media and the actual situation of soil around the ground buried tube heat exchanger, a sand box test bed is built. The thermal transport characteristics of saturated-unsaturated region at different ambient temperatures were investigated. In the process of research, grey Markov model is applied to study the trend and randomness of heat transfer. The results show that the heat transfer characteristics of saturated and unsaturated regions are different. No seepage, different seepage velocity, different cold / heat source temperature, different ambient temperature have different effects on the heat transfer in saturated-unsaturated region. Under the condition of no seepage, the heat in the saturated region is transferred from the heat source to the external heat source, and the heat transfer characteristics in the unsaturated region are similar to those in the saturated region, but there is no obvious difference. The random temperature is within 1 鈩，
本文编号：2379935
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