太阳能-埋管换热器增温填埋垃圾技术的性能研究

RESEARCH ON PERFORMANCE OF TECHNOLOGY OF HEATING LANDFILL WITH SOLAR COLLECTOR-BURIED PIPE HEAT EXCHANGER

填埋垃圾的厌氧发酵需要较高的温度,由于中国北方地区冬季的气温低,垃圾填埋场的厌氧发酵速度较慢。为解决这一问题,提出太阳能-埋管换热器增温填埋垃圾技术,建立垃圾填埋体及其周边区域的3D物理模型,采用试验和数值模拟的方法,对垃圾填埋体内部的增温效果和传热性能进行了研究,并对试验结果和数值模拟结果进行了相互对比验证。研究结果表明:埋管密集处垃圾填埋体的温度变化显著,热量向上传递多于向下传递;在晴天白天,埋管换热量呈现先升高后降低的变化趋势;2021年9月23日—12月21日,垃圾填埋体的日平均温度的平均值为36.3℃,增温加热期内,垃圾填埋体传热系数的平均值为32.5 W/(m^(2)·K);随着埋管内水流量在0.4~1.0 m^(3)/h内增加,垃圾填埋体的日平均温度和单位体积换热功率均逐渐增加,且增加趋势逐渐平缓,埋管内水流量增加至1.0 m^(3)/h时,模拟得到的垃圾填埋体日平均温度为37.0℃,单位体积换热功率为52.9 W/m^(3)。

The anaerobic fermentation of landflll requires a higher temperature,and due to the low temperature in winter in northern China,the anaerobic fermentation rate in landflll sites is slower.To solve this problem,this paper proposes the technology of heating landflll with solar collector-buried pipe heat exchanger,establish a 3D physical model of the landflll body and its surrounding area.Experimental and numerical simulation methods are used to study the temperature increase effect and heat transfer performance inside the landflll body,and the experimental results and numerical simulation results are compared and verifled.The research results show that the temperature change of the landflll body in densely buried pipes is signiflcant,and heat is transmitted upwards more than downwards.During sunny days,the heat transfer of buried pipes shows a trend of flrst increasing and then decreasing.From September 23rd to December 21st,2021,the average value of daily average temperature of the landflll body is 36.3℃,and the average heat transfer coefflcient of the landflll body during the heating period is 32.5 W/(m^(2)·K).As the water fiow rate in buried pipe increases between 0.4 and 1.0 m^(3)/h,the daily average temperature and unit volume heat transfer power of the landflll body gradually increase,and the increasing trend gradually becomes gentle.When the water fiow rate in buried pipe increases to 1.0 m^(3)/h,the simulated daily average temperature of the landflll body is 37.0℃,and the unit volume heat transfer power is 52.9 W/m^(3).