集中燃烧式原位热脱附技术装备研发与中试应用

针对污染土壤原位热脱附修复技术能耗较高造成的应用局限,通过集中燃烧、余热回收等方式来提高加热装置的能源利用效率,研发了低能耗集中燃烧式原位热脱附技术装备,并在上海某有机污染场地中试应用。中试运行结果表明,该项技术装备加热性能良好,应用于有机污染场地原位热脱附修复工程总体可行,能够达到传统的分散燃烧式原位热脱附系统的加热效能,节能降耗效果显著,可以降低15%左右的能耗。     

原位热脱附修复污染土壤加热效果模拟和试验研究

原位热脱附技术具有工艺原理简单、效率高、安全稳定等显著优点,能有效应对污染企业被迫搬迁、改造和关停后所产生的污染场地遗留问题.通过FLUENT软件模拟单根加热棒在土壤中的加热过程,结果表明,加热棒能对周围污染土壤进行有效升温,随着加热时间的增加,土壤温度逐渐升高;同时,测温点距离加热棒表面越近,则温度越高.因此,热脱附...     

热除菌型Trombe墙系统性能研究

热除菌利用细菌在高温下失活的原理,是一种安全、有效、环保的杀菌方法。将热杀菌技术与Trombe墙结合,提出一种热除菌型Trombe墙系统,能同时实现建筑室内采暖和热杀菌功能。围绕提出的除菌型Trombe墙进行墙体热性能实验研究,探究墙体全天的热性能;同时建立系统传热热传质模型,进行室内典型细菌的热失活分析。结果表明,在环境温度为18.1℃、太阳辐射强度为620.6 W/m²的实验条件下,日均空气热效率为0.46;对于大肠杆菌、利斯特氏菌、植物乳杆菌、山夫顿堡沙门氏菌和酿酒酵母五种细菌,热除菌产生的洁净空气量在0～40 m³/h范围内,全天净空气总产生量分别为94.01 m³/(m²·d)、86.51 m³/(m²·d)、100.70 m³/(m²·d)、94.95 m³/(m²·d)和100.10 m³/(m²·d);当换气次...     

基于竖缝式鱼道的鱼类上溯试验研究

为分析影响鱼类上溯的影响因素，基于竖缝式鱼道对19～27 cm体长范围内的鲫鱼开展连续上溯试验。通过物理模型和数值模拟相结合的方法，对鲫鱼上溯过程的位置与数值模拟得到池室内部的流速场和紊动能叠加分析，得到鲫鱼上溯所喜好的流速范围。试验结果表明，体长为19～27 cm的鲫鱼上溯所喜好的池室流速范围为0.091～0.524 m/s,试验中水流的紊动能最大值为0.035 6 m²/s²,小于0.050 m²/s²,属于低紊动能区，适合鱼类上溯，鱼类在上溯过程中会寻找流速和紊动能低的地方进行上溯。研究成果可为其他鱼类上溯提供参考。     

泡沫混凝土作为原位土壤热修复隔热层的研究

原位热修复场地表层土壤采用有效的隔热措施,有助于实现节能降耗.泡沫混凝土是一种新型轻质保温材料,导热系数低,可作为原位热修复场地的表面阻隔材料.通过计算敷设的泡沫混凝土在不同环境条件下的散热损失,分析、讨论其隔热性能和特点,得到以下结论:泡沫混凝土作为原位热修复工程场地表层阻隔材料,在不同环境条件下,均可起到较好的隔热...     

围护结构动态热响应机理及应用

动态性是围护结构传热的本质属性，动态热响应机理是其动态运行规律的体现。围护结构在夏季的动态性比在冬季表现更为典型，因此该文开展隔热建筑的围护结构动态性机理及应用研究。通过研究围护结构的动态热响应机理提出围护结构最大防热量G_max，该指标兼顾多种工况下围护结构热性能的评价。以夏热冬冷地区的重庆为例进行模拟分析。研究发现：G_max<60 W/m²时，提升墙体最大防热量可有效提升其动态热响应性能；G_max在60～90 W/m²之间时，提升墙体最大防热量可较少提升其动态热响应性能；G_max>90 W/m²时，提升墙体最大防热量反而会降低其动态热响应性能。     

基于热平衡原理的地埋管地源热泵系统开发利用潜力评价

以淮河生态经济带（江苏段）地埋管地源热泵系统开发利用潜力为研究对象,通过数值模拟的方法,模拟预测地埋管地源热泵系统运行期间地下温度场的变化趋势,确定2种能缓解热堆积问题的地埋管地源热泵系统开发利用方案,并以此为基础评价研究区地埋管地源热泵系统开发利用潜力。结果表明：2种方案下研究区夏季平均制冷潜力分别为7412.35、37863.31 m²/km²;冬季平均供暖潜力分别为16660.87、81316.84 m²/km²。     

质量含水率对土壤温度场影响的试验研究

搭建土壤换热实验台,研究非饱和土壤换热时土壤质量含水率对土壤温度场的影响。采用恒温水作为热源,分别在4种土壤质量含水率工况下进行试验,研究土壤温度变化情况,试验用土壤在非饱和工况下加热10 h后的热影响半径约为680 mm,质量含水率越低的土壤受到的热扰动越剧烈。     

海上天然气处理平台节能降耗措施探讨

天然气作为绿色低碳能源,其开采过程中也会伴随大量的二氧化碳排放。某天然气处理平台在生产过程中,根据不同的系统或工况实施了一系列的工艺、设备和逻辑改造,在保障系统安全稳定运行的同时,极大地减少了天然气开采过程中的碳排放量。通过将三甘醇系统气提气由天然气改为氮气、尾气流程加装冷却器,年节省天然气消耗30×10⁴m³,回收轻烃122m³;对凝析油外输泵进行逻辑改造,将流量控制阀FV的控制模式由单一的流量PID控制,改为流量和频率串级控制,实现流量设点随频率的变化而变化,外输泵能耗降低3%,缓冲罐闪蒸气量降低约1000m³/d;通过天然气增压工艺参数适应性优化,在平均湿气输送量1400×10⁴m³/d的前提下,日均耗气由20.27×10⁴m³/d降至14.75×10⁴m³/d,每天节省燃气5.52×10⁴m³;通过新增高压和低压火炬气...     

活化和热解气氛对半焦基活性炭性能的影响

以煤炭分级转化半焦为原料，采用廉价烟气活化法制备适用于小分子污染物吸附脱除的活性炭，分别从活化工况、活化气氛、热解气氛三方面探究并对比了其物化性质和吸附性能。结果表明：分级转化半焦经烟气活化，在最优工况下可以得到比表面积为798.27 m²/g的活性炭，其微孔体积为0.327 cm³/g，碘值可达1056.84 mg/g。当固定烟气气氛中两种组分的浓度时，活性炭的碘值、比表面积和微孔结构随第三种组分浓度的增加呈现先升后降趋势。对比氮气热解半焦和模拟煤炭分级转化多联产系统的煤气热解半焦所制的活性炭，煤气半焦活性炭比表面积、微孔体积和碘值均有所提高，同时可以显著降低能耗，最优活化时间降低50%，经济性较好。     

Performance study on heat and moisture transfer in soil heat charging

In some cold areas, the system performance of the soil source heat pump system is reduced by the decreasing underground soil temperature, which is caused by the thermal imbalance between the heating demand in winter and the cooling demand in summer. Soil heat charging with solar energy in non-heating seasons is proposed for solving the problem. It has been found from previous studies that the effect of the moisture transfer on the heat transfer within porous media could not be neglected especially under higher temperature difference. Therefore, this paper provides an investigation on the heat and moisture transfer in soil during soil heat charging at high temperature. A numerical model is developed for the study. The simulation results are compared with the testing data from the authors' previous study for the model verification. Based on the verified model, the performance of the heat and moisture transfer in soil during soil heat charging in a longer time and a larger area is investigated in the paper. The results show that the testing data match very well with the simulation results within a relative error of ±9% and the mathematical model is reliable for the performance prediction of heat and moisture transfer in soil heat charging. The soil volumetric water content (VWC) distribution tends to be stable after soil heat charging for 13 days and the heat source has an effective influence on soil VWC distribution within 2.4?m. The effect of the heat source temperature and initial VWC on the soil temperature and VWC distribution and heat power is proved to be obvious. Loam has a better performance in soil heat charging than sand.     

大气对流对土壤内热湿迁移影响的实验研究

对土壤内热湿迁移过程进行了研究,通过对土壤内热湿迁移机理分析,根据质量守恒和能量守恒原理,建立了土壤非饱和区热湿迁移的理论模型,对大气对流环境条件下砂土内热湿迁移过程进行了实验研究,实验测量和数值计算,获得了不同大对流速度作用下土壤中温度,含水率分布以及水分蒸发强度的变化。     

Experimental investigation of thermal and moisture behaviors of wet and dry soils with buried capillary heating system

An experimental study of thermal and moisture behaviors of dry and wet soils heated by buried capillary plaits was done. This study was carried out on a prototype similar to an agricultural tunnel greenhouse. The experimental procedure consisted on three different measuring phases distinguished by three different operational conditions of the capillary plaits: heating at 70 °C, heating at 40 °C and without heating in summer. During an experimental run, quantities measured are soil temperature, soil water content at various depths, soil surface heat flux, solar radiation under the plastic cover, internal relative humidity, internal and external air temperature. In unsaturated moist soils, the transport of heat is complicated by the fact that heat and mass transfer is a coupled process. During the daily soil temperature variation, it was found that the surface temperature amplitude was higher in wet soil than in dry soil. The water content increased during daytime and decreased during nighttime. The diurnal variation amplitude of water content was higher without underground heating and decreased with the buried heat source temperature.     

土壤高温储热热湿迁移过程的初步研究

初步建立了土壤高温储热热湿迁移过程的数学模型,并进行了数值求解.结果表明,土壤热湿迁移过程中的湿度场稳定时间明显滞后于温度场,且与土壤类型和水力传导特性等有关.对于水力传导性较差的土壤,在高温储热初期,靠近热源的地方容易产生湿份聚集,使得湿度曲线出现一个短期峰值.与低温储热相比,土壤高温储热时湿度迁移对温度场的影响较大,温度场呈整体降低趋势,降低幅度顺序为:砂土>壤土>粘土.在该文模拟条件下,粘土的热湿迁移过程对于初始湿度的变化不敏感,而砂土的热湿迁移过程则依赖于初始湿度,且影响程度随着初始湿度的增加而增大.     

太阳辐照条件下土壤内温湿度场的动态模拟

根据质量守恒和能量守恒定律，同时对土壤非饱和区热湿迁移机理进行分析，建立了土壤非饱和区热湿迁移的理论模型。通过数值分析，模拟了太阳辐照条件下土壤内温度和含水率分布曲线。     

地源热泵间歇运行下土壤热湿迁移的实验研究

建立地埋管换热土壤热湿迁移过程的实验装置,对地源热泵间歇运行时不同进口流体温度及不同土壤体积含水率下土壤温湿度场的变化特性进行实验研究。实验结果表明∶间歇运行时,入口流体温度的升高会使土壤温度最大值升高,但不利于土壤温度的恢复,土壤体积含水率的增加在一定程度上有利于地下换热和土壤温度的恢复。系统开机后存在土壤温度上升的主上升区,此区温度增幅超过65%,关机后第18小时土壤温度基本恢复至初始温度;系统关停后在温湿度梯度的作用下会出现温度和含水率最大值后移的现象,热源对土壤温度和含水率的作用半径约为280和375 mm;开停比为1∶2时温湿度较1∶1能恢复得更低,合理设置停机时间有利于机组长期有效运行。     

Influence of soil moisture content on soil solarization efficiency

Soil temperature under plastic cover is a function of incoming radiation and thermal characteristics of the mulching material and the soil. A field experiment was conducted at Fudhiliyah Agrometeorological research station to investigate how soil temperature is influenced by different soil moisture content regimes during soil solarization. Two soils, sandy loam and silty clay loam, were brought to five volumetric moisture regimes (M1–M5). The moistened soils were mulched with 180-μm-thick transparent polyethylene. Measurements of hourly soil temperatures for depths of 0.00, 0.05, 0.10 and 0.30 m were recorded from 1 June to 30 September. The results showed that the maximum soil temperatures decreased with increasing soil moisture content. The relationship between the hourly rise in soil temperature and heat flux were significantly affected by soil moisture content. Moreover, soil solarization efficiency decreased with increasing moisture content. The higher temperatures in both soils under the M4 irrigation regime resulted in faster eradication of the pathogenic fungus, Fusarium oxysporum (sp. lycopersici).     

Numerical investigation into mutual effects of soil thermal and isothermal properties on heat and moisture transfer in unsaturated soil applied as thermal storage system

In this article, a numerical model for simulation of the heat and mass transfer phenomena in unsaturated soil is presented. The system is provided to evaluate its behavior as a thermal storage system. The model includes a single pipe that is buried under unsaturated media which is connected to a source with the constant heat rate of 20 W/m³ in sandy soils during a specific time. All the numerical results show good agreement with previous results, thus excellent correlation was achieved. Additionally, sensitivity analysis is done to clear up the role of the thermal and isothermal properties respect to volumetric water content and temperature and to assess the effects of related parameters on heat transfer in the media. The results show that as getting far away from the source, in addition to reduce the collected energy, the intensity of increasing the temperature and decreasing the moisture diminished will be more. Generally over time, the cumulative stored energy for each point will tend to a constant quantity.     

Numerical investigation of the performance and soil temperature recovery of an EATHE system under intermittent operations

One of the problems in operating earth air tunnel heat exchangers (EATHE) for cooling in summer, with soil having high specific heat and low moisture content is accumulation of heat around the pipe. The low rate of heat dissipation due to conduction restricts the performance of EATHE over subsequent years. In the present paper, numerical simulations have been performed to investigate the thermal performance and soil temperature during summer operation in Jaipur to estimate extent of soil degradation. The simulation result indicates that by the end of summer, the soil leads to thermal saturation which in turn, may render it unusable for next summer. This scenario demands for heat removal through force convection. Three strategies namely, night purging during summer operation, day operation during winter and night operation during winter were attempted to estimate extent of soil recovery. Simulation results show that the average COPs for summer, summer with night purging, winter day and winter night operation mode are 4.23, 3.68, 5.01, and 6.65 respectively. It was found that advantage of night purging is less than energy required to run blower for night purging. However, winter day/night operation offers space heating and better soil for next summer.     

A quasi-3D analysis of the thermal performance of a flat heat pipe

The thermal performance of a flat heat pipe thermal spreader has been described by a quasi-3D mathematical model and numerically modeled. An explicit finite volume method with under-relaxation was used for computations in the vapor phase. This was combined with a relatively small time step for the analysis. The physical problem consisted of an evaporator surface that was transiently heated non-uniformly for a short period of time and the heat source then removed. Then the system was cooled by natural convection and radiative heat transfer at the condenser region. The transient temperature distributions at the front and back of the heat spreader were obtained for different times during the transient period. The velocity distribution in the vapor core was also obtained. Due to the effect of phase change at the evaporator and condenser sides, a significant amount of energy is found to be absorbed and partially released during the transient heating and cooling processes. The numerical results indicate that advection and the high thermal diffusivity of the vapor phase accelerate the propagation of the temperature distribution in the vapor core, making it uniform during this process. The condenser temperature distribution was almost uniform at the end of the transient heating process. The transient temperature distribution on a solid aluminum plate was compared with the flat heat pipe results and indicated that the flat heat pipe successfully spread the heat uniformly at the condenser side of the structure.