电子设备的微型化、集成化发展，使其内部热流密度急剧升高，对散热技术提出挑战。微通道流动沸腾换热能力强，是高热流密度散热问题的潜在解决方案。而在常规的实体肋微通道中，因汽泡生长受限引起的蒸汽回流现象会导致严重的流动不稳定和换热性能恶化。针对该问题，本文以水为工质，以泡沫铜肋微通道热沉为研究对象，系统探究了流动参数和通道结构对流动沸腾的流型、换热特性、压降特性及流动稳定性的影响规律。论文首先通过可视化方法得到了通道中流型演化过程，观察到汽液两相流体在泡沫铜肋中存在横向流动，横向流动平衡了通道间压力，显著增强了流动稳定性。研究了流动参数对换热系数的影响规律。在相同质量流速下，换热系数随热流密度或蒸汽干度增加先增大后减小；随蒸汽干度增大，换热机理从核态沸腾向薄膜蒸发过渡。在高热流密度时，观察到泡沫铜肋微通道中存在同步回流现象，其引起的间歇性烧干是换热恶化的直接原因。研究了泡沫铜的孔隙率和肋宽与通道宽之比（肋宽比）对流动沸腾换热的影响。孔隙率对换热的影响与蒸汽干度相关，受到换热面积和肋区补液阻力两方面因素的影响。低蒸汽干度时，液体补充容易，换热面积是主导因素；高蒸汽干度时，蒸汽溢出和液体补充阻力增大，从而主导换热。改变肋宽比影响通道底面积和泡沫铜肋面积的比例。肋区面积的利用率随肋宽增加而减小。存在最佳的肋宽比使换热最优。针对实体铜通道底面泡沫铜肋微通道，考虑质量流速、热流密度、蒸汽干度、孔隙率和肋宽比的影响，整理获得了两相换热系数关联式和两相摩擦压降关联式。针对泡沫铜肋微通道，提出了提高肋效率和利用流体惯性冲刷补液的换热增强手段，并分别设计了泡沫铜通道底面和波浪形通道结构。与实体铜通道底面相比，泡沫铜通道底面结构显著增强了换热恶化出现前的换热性能，换热系数最大提升75%。与泡沫铜肋直通道相比，波浪形通道结构提高了低流量下出现烧干的蒸汽干度，显著增强了换热开始恶化后的换热性能，换热系数最多提高193%。对比了泡沫铜肋微通道和实体肋微通道的流动沸腾性能。在换热方面，泡沫铜肋增大换热面积，延缓烧干并减少烧干时间。与实体肋结构相比，泡沫铜肋结构换热系数最多提高99%；在流动稳定性方面，泡沫铜肋平衡了通道间压力，显著增强流动稳定性。与实体肋结构相比，本文9种泡沫铜肋结构在所有工况下，压降波动平均减小61%～71%，壁温波动平均减小66%～80%。

The miniaturization and integration of electronic devices have led to a sharp increase in their internal heat flux, which raises a challenge to heat dissipation technology. Flow boiling in microchannels, known for its high heat transfer capability, has emerged as a promising solution for high heat flux dissipation. However, in conventional solid fin microchannels (SFMC), the confinement of bubbles often leads to vapor backflow, which in turn causes flow instability and deteriorates heat transfer performance. To address this issue, this dissertation takes water as the working fluid and copper foam fin microchannels (CFFMC) as the research object, and systematically investigates the effect of flow parameters and channel structure on the flow patterns, heat transfer characteristics, pressure drop characteristics and flow stabilities.The dissertation first obtained the evolution of flow patterns in the channels by the visualization method. The transverse flow of two-phase fluid through the copper foam fin was identified. This transverse flow balances the pressure between channels and significantly improves flow stability. The effect of flow parameters on the heat transfer coefficient (HTC) was investigated. It was observed that the HTC first increases and then decreases with increasing heat flux or vapor quality at a given mass flux and the heat transfer mechanism transitions from nucleate boiling to thin film evaporation as the vapor quality increases. Under high heat flux conditions, synchronized backflow was found in the CFFMC, leading to intermittent dry-out and causing heat transfer deterioration directly.The effects of the porosity of copper foam and the ratio of fin width to channel width (fin-channel width ratio) on flow boiling heat transfer in CFFMC were studied. The effect of porosity on heat transfer is related to vapor quality and is affected by both the heat transfer area and the replenishment resistance in the fin. At low vapor quality, liquid replenishment is easy, and heat transfer area is the dominant factor. At high vapor quality, the vapor escape and liquid replenishment resistance increase, thus dominating the heat transfer. The fin-channel width ratio affects the proportion of the channel bottom area and copper foam fin area. The utilization efficiency of fin area decreases with increasing fin width. There exists an optimal fin-width ratio corresponding to the best heat transfer performance. An HTC correlation and a two-phase frictional pressure drop correlation were proposed for CFFMC with solid copper channel bottoms, considering the effects of mass flux, heat flux, vapor quality, porosity and fin-channel width ratio.Methods to enhance fin efficiency and utilize fluid inertia for liquid replenishment were proposed to improve the heat transfer of CFFMC. The structures of CFFMC with copper foam on the channel bottoms and wavy-CFFMC were designed. Compared with the CFFMC with solid copper on the channel bottoms, the structures of CFFMC with copper foam on the channel bottoms significantly enhance heat transfer performance before the appearance of heat transfer deterioration, with a maximum increase in HTC of up to 75%. Compared with the straight-CFFMC, the wavy-CFFMC structure delays intermittent dry-out vapor quality at low mass flow rates and greatly enhances heat transfer performance after the appearance of heat transfer deterioration, with a maximum increase in HTC of up to 193%.The flow boiling performances of SFMC and CFFMCs were compared. In terms of heat transfer, copper foam fin increases the heat transfer area, delays dry-out and reduces the dry-out duration. Compared with SFMC, the HTC of CFFMCs is increased by up to 99%. Regarding flow stability, copper foam fin balances inter-channel pressures, and significantly improves flow stability. Compared with SFMC, the pressure drop fluctuation of the nine CFFMC structures in this dissertation is reduced by an average of 61% to 71% under all operating conditions, and the wall temperature fluctuation is reduced by an average of 66% to 80%.