如图1所示，盘管式热虹吸管通过热气体管道中的蒸发器盘管和冷却器气体管道中的冷凝器盘管之间的两相中间工作流体的自然循环来交换热量。由于这些区域之间的蒸汽压差，蒸汽从蒸发器流向冷凝器，这是因为较热的蒸发器盘管中的液-汽界面温度和饱和压力将始终超过较冷的冷凝器盘管中的饱和压力。盘管和互连管道的配置必须确保冷凝水不会泄漏。通过重力返回加热器蒸发器盘管。如果盘管的布置如图lb所示，其中一个盘管中没有液体中间流体，那么该盘管只能充当冷凝器，系统只能向一个方向传热。这种系统据说是单向的。如果两个盘管都含有液体中间流体，如图。 la，那么这个系统能够在两个方向上传递热量，据说是双向的。本论文基于对ASHRAE进行的一项大型研究（被称为“研究项目188”）的结果，仅关注单向盘管热虹吸换热器的性能。由ASHRAE as RP 140支持的一项早期研究涉及单管热虹吸回路，如图2所示。在这项研究中发现，当冷凝器中没有残留液体，且蒸发器顶部出现接近干涸时，热虹吸回路达到最佳性能。不幸的是，如果蒸发器和冷凝器管之间的温差发生变化，则给定系统无法保持这种理想状态。在目前的研究中，通过在蒸发器上添加分离器和液体再循环管，将该限制降至最低，如图所示。 3.该系统通过两种方式抑制干燥的开始:首先，允许蒸发器中携带更高的电荷，而不会受到与液体携带有关的惩罚（蒸汽管中的压降大幅增加，液膜增厚导致冷凝系数降低），其次，当所有工作流体必须在整个系统中循环时，允许通过蒸发器管的流速高于之前可能的流速。为了研究图3所示类型的热虹吸回路的性能，开发了一个计算机模拟程序，对实验结果进行了测试，然后用于研究各种条件下的回路行为。本文概述了这一点。doneand展示了单向盘管式热虹吸装置的特征行为。引文:新墨西哥州阿尔伯克基市阿什雷学报第84卷第2部分

A coil loop thermosiphon exchanges heat by virtue of the natural circulation of a two-phase intermediate working fluid between an evaporator coil in the hot gas duct and a condenser coil in the cooler gas duct as shown in Fig. 1. The vapor flows from the evaporator to the condenser due to a vapor pressure difference between these regions, which arises because the liquid vapor interface temperature and hence the saturation pressure in the warmer evaporator coil will always exceed that in the cooler condenser coil. The configuration of the coils and interconnecting piping must be such that the condensate will.return by gravity to the warmer evaporator coil. If the coils are arranged as shown in Fig. lb, where no liquid intermediate fluid resides in one of the coils, then that coil can only act as a condenser and the system will transfer heat in only one direction. Such a system is said to be unidirectional. If both coils contain liquid intermediate fiuid, as in Fig. la, then the system is capable of trans'ferringheat in both directions and is said to be bidirectional.This paper, which is based on the results of a larger study carried out for ASHRAE, designated as "Research Project 188", is concerned only with the performance of unidirectional coil loop thermosiphon heat exchangers. An earlier study, supported by ASHRAE as RP 140, dealt with single tube thermosiphon loops such as that illustrated in Fig. 2. In this study it was found that a thermosiphon loop achieves its best performance when no resident liquid is present in the condenser and when near dryout occurs at the top of the evaporator. Unfortunately this ideal condition cannot be maintained for a given system if the temperature difference between the evaporator and the condenser tubes changes. In the current study this limitation has been minimized by the addition of a separator and a liquid recirculation tube to the evaporator as illustrated in Fig. 3. This system suppresses the onset of dryout in two ways: first, by permitting a higher charge to be carried in the evaporator without the penalties associated with liquid carryover (substantially higher pressure drops in the vapor pipe and reduced condensation coefficients resulting from thicker liquid film), and second,by permitting a higher flow rate through the evaporator tubes than was previously possible when all the working fluid had to circulate around the entire system.In order to investigate the performance of thermosiphon loops of the type illustrated in Fig. 3, a computer simulation program was developed, tested against experimental results, then used to study loop behavior under various conditions. This paper outlines how this was.doneand shows the characteristic behavior of unidirectional coil loop thermosiphons.