The topic of boiling heat transfer in miniscale geometries has focused the ever increasing interest of researchers in recent years. However, most of the works are related to mini- and microchannels and much less to minigaps. Meanwhile, minigaps allow for more comprehensive experimental studies, i.e. flow visualisations due to the flat, two-dimensional configuration of the flow. The results of the experimental investigations of a model plate heat exchanger, composed of a single plate with a heat exchange surface of 0.1 m x 0.2 m, made of brass are presented. The working fluid is pure ethanol. Between the plate and the cover of the exchanger, 0.5 mm and 1.0 mm thick minigaps are arranged. The 0.5 mm minigap has been compared to an equivalent minichannel structure (a set of 50 parallel minichannels) with an equal cross-sectional area (rectangular 1 mm x 1 mm). An attempt to intensify the heat exchange by modifying the minigap wall was made. Two variants were tested to check the potential increase in the heat transfer coefficient and flow resistance. The section cover is transparent in order to simultaneously register the flow structures with the measurements. The heat is supplied using a water circuit, where the temperature and flow of the water can be regulated in a constant temperature water tank. The flow configuration of the exchanger is countercurrent, with the vertical flow of ethanol from the bottom to the top. The inlet and outlet manifolds are arranged as trapezoidal (Z-type design). The authors have analysed the efficiency of heat transport and pressure drop depending on the system operating parameters. The visualisations are thoroughly analysed to better understand the process. The main advantages of the presented work are a direct comparison of minigap and minichannel structures while standardising all other parameters; an interesting application of a simple, passive heat transfer intensification method which resulted in the unification of the velocity fields in the minigap and reduced maldistribution.

近年来，小型几何结构中沸腾传热的话题引起了研究人员越来越多的兴趣。但是，大多数作品都与微型通道和微通道有关，而与微型间隙相关的则少得多。同时，最小间隙允许进行更全面的实验研究，即由于流动的二维平面配置而使流动可视化。给出了由黄铜制成的模型板式热交换器的实验研究结果，该模型板式热交换器由热交换表面为0.1 m x 0.2 m的单个板组成。工作流体是纯乙醇。在交换器的板和盖之间，布置了0.5毫米和1.0毫米厚的小间隙。0。将5毫米的微型间隙与具有相同横截面积（矩形1毫米x 1毫米）的等效微型通道结构（一组50个平行微型通道）进行了比较。尝试通过修改微间隙壁来加强热交换。测试了两个变体，以检查传热系数和流阻的潜在增加。分段盖是透明的，以便同时将流量结构与测量结果对齐。使用水回路提供热量，在水回路中，可以在恒温水箱中调节水的温度和流量。交换器的流动配置为逆流，乙醇从底部到顶部垂直流动。入口和出口歧管布置为梯形（Z型设计）。作者根据系统运行参数分析了热传输效率和压降。对可视化进行了全面分析，以更好地了解过程。提出的工作的主要优点是在对所有其他参数进行标准化的同时直接比较了微间隙和微通道结构；一个简单的被动传热强化方法的有趣应用，该方法导致了最小间隙中速度场的统一并减少了分布不均。