| 基于热技术的活立木液流测量方法综述 |
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| 引用本文： | 宋博华,高歌,高珊,孙琳琳,李冰雪.基于热技术的活立木液流测量方法综述[J].浙江农林大学学报,2022,39(2):456-464. |
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| 作者姓名： | 宋博华 高歌 高珊 孙琳琳 李冰雪 |
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| 作者单位： | 东北林业大学 工程技术学院，黑龙江 哈尔滨150040 |
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| 基金项目： | 国家自然科学基金资助项目(32071685, 31600453)；黑龙江省自然科学基金联合引导项目(LH2019C002) |
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| 摘 要： | 比较不同研究目标和实验条件下适用的基于热技术的树干液流测量方法，展望不同热技术方法在液流测定中的应用前景，为活立木液流测量的方法选择提供参考。目前常用的基于热技术的液流检测方法包括热脉冲法、热平衡法、热扩散法、热场变形法和外热比法等5种。其中，热脉冲法通过测定热脉冲到达热电偶处所需的时间来计算液流速率，热平衡法通过加热元件输入的热量、热传导以及液流携带热量之间的能量平衡关系计算液流。而热扩散法、热场变形法和外热比法则是利用温度差值来表征树液流动产生的热场变化，进而确定液流速率和液流密度。近年来，结合相关热技术原理对已有热技术方法进行了改进，热平衡法、热场变形法和外热比法的测定精度有所提高。但热场变形法的测定过程较为复杂，外热比法的外部量规配置尚待探讨，应用并不广泛。热扩散法和热脉冲法虽然已经具备较成熟的商品化产品，但测定精度仍存在问题。液流速率的检测精度直接影响研究结果的准确性。在测定液流速率时，需依据不同条件选择适合的方法，从而有效提高液流速率的测定精度。图1表1参58
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| 关 键 词： | 树干液流 热脉冲法 热平衡法 热扩散法 热场变形法 外热比法 |
| 收稿时间： | 2021-04-15 |
Overview of the methods for sap flow measurement of standing tree based on thermal technology |
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| SONG Bohua,GAO Ge,GAO Shan,SUN Linlin,LI Bingxue.Overview of the methods for sap flow measurement of standing tree based on thermal technology[J].Journal of Zhejiang A&F University,2022,39(2):456-464. |
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| Authors: | SONG Bohua GAO Ge GAO Shan SUN Linlin LI Bingxue |
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| Institution: | College of Engineering and Technology, Northeast Forestry University, Harbin 150040, Heilongjiang, China |
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| Abstract: | With the comparion of the five thermal methods commonly used for trunk sap flow measurement with the focus on their respective advantages and disadvantages under different research objectives and experimental circumstance, this study is aimed to provide reference for practices in liquid flow measurements of standing trees. Of the five thermal methods commonly employed, Heat Pluse Velocity Method (HPVM) has mainly been used to calculate the flow rate by measuring the time required for the heat pulse to reach the thermocouple. Heat Balance Method (HBM) is used to calculate the sap flow by means of the energy balance between the heat input via the heating element, the heat conduction and the heat carried by the sap flow. Whereas Thermal Dissipation Method (TDM), Heat Field Deformation (HFD), and External Heat-Ratio (EHR) all use the temperature difference to characterize the thermal field changes caused by the sap flow before the sap flow rate and density are determined. In recent years, with the employment of relevant thermal technology, researches aimed to improve the existing thermal technology methods have been rewarded with higner sap flow measurement accuracy of HBM, HFD and EHR. Neither HBM nor EHR has been widely employed due to the complex measurement process and uncertainly in the configuration of the micro external gauge respectively. TDM and HPVM still suffer from low accuracy of determination despite the relatively mature commercial products of them. In conclusion, improperly selected determination methods will lead to great deviation in research rusults, therefore, is it proposed that suitable methods should be chosen in accordance with different experimental conditions so as to better promote the measurement accuracy of tree sap flow. Ch, 1 fig. 1 tab. 58 ref.] |
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