图1为两种微流体在装置内混合的示意图。在微流控芯片内腔为分布有大量孔隙的筛板结构。微流体中的成分通过混沌平流进行混合，在流经折回弯道时，混沌平流得到加强。在微流控混合器中，两种微流体的接触面积大大加强，大幅度增加了混合效果。微流控混合器内通道间的间隙仅10-100微米。设备内微流体的流量一般在微升每秒级别，流道直径为10微米，微混合器高度约为100微米。

Figure 1 shows the mixing of two microfluidics in the device. The cavity of the microfluidic chip is a sieve plate structure with a large number of pores. The components in the microfluidic are mixed by chaotic advection, which is enhanced as it flows through the returning-back curve. In the microfluidic mixer, the contact area of the two microfluidics is greatly strengthened, which greatly increases the mixing effect. The gap between channels in the microfluidic mixer is only 10-100 microns. The flow rate is generally in the order of microliters per second, the flow diameter is 10 microns, and the height of the micromixer is about 100 microns.

图1 微流控混合器

Figure 1 Microchannel Mixer

图2为复合型薄流层混合器的扫描电子显微图。该装置由2 × 15个交错微通道和波纹壁组成。待混流体逆流进入混合器，流入波纹壁面的交错通道。流道宽度一般为25至40微米。通道的结构导致了两种流体呈周期性流动。流体沿进料的垂直方向流出混合器，由于每层板的厚度足够薄，所以流体之间通过扩散达到快速混合的效果（如图3所示）。波纹槽壁增加了流体的接触面，提高了分离壁的机械稳定性。

FIG. 2 shows the scanning electron micrograph of a composite thin-layer mixer. The device consists of 2 × 15 staggered microchannels and corrugated walls. The fluid to be mixed counterflows into the mixer and flows into a staggered channel on the corrugated wall. The channel width is generally 25 to 40 microns. The structure of the channel causes the two fluids to flow periodically. The fluid flows out of the mixer in the vertical direction of the feed, and since the thickness of each layer is thin enough, the fluid is diffused to achieve rapid mixing (as shown in Figure 3). The corrugated groove wall increases the contact surface of the fluid and improves the mechanical stability of the separation wall.

图2 复合型薄流层混合器的扫描电子显微图

FIG. 2 Scanning electron micrograph of a composite thin-layer mixer

图3 流体之间通过扩散混合示意图

Figure 3 Schematic diagram of mixing between fluids by diffusion

图4为堆叠板错流换热器（错流微换热器的核心部件，由多层横向定向的金属板片组成）。为了有效地将热量从一种流体传递到另一种流体，除了需要足够大的接触面积和温度梯度外，还有另一个重要的准则是传热与压力损失的比率。流体流被分成许多微小流（如板式热交换器）。这些局部流体通常呈现低雷诺数特点，往往是层流状态而不是湍流状态。减小流道的尺寸增大了温度梯度和交换面体积比，即小型化的换热器会有更好的换热效果。流动尺寸的减小不可避免地与粘性损失的增加有关，但总体传热压力损失比得到了改善。

Figure 4 shows the stacked plate cross-flow heat exchanger (the core component of the cross-flow micro-heat exchanger, consisting of multiple layers of transversally oriented metal sheets). In order to effectively transfer heat from one fluid to another, in addition to the need for a sufficiently large contact area and temperature gradient, another important factor is the ratio of heat transfer to pressure loss. The fluid flow is divided into many tiny flows (such as plate heat exchangers). These local fluids are typically characterized by low Reynolds numbers and tend to be laminar rather than turbulent. Reducing the size of the flow path increases the temperature gradient and the volume ratio of the exchange surface, that is, the miniaturized heat exchanger will have a better heat transfer effect. The decrease of flow size is inevitably associated with the increase of viscosity loss, but the overall heat transfer pressure loss ratio is improved.

图4 堆叠板错流换热器

Figure 4 stacked plate cross-flow heat exchanger

微换热器的核心结构由约100个薄板组成，体积约几平方厘米，包含矩形微通道，横向堆叠并密封连接，形成传热流体和工艺流体的两个独立通道，约有4000个微通道。单个微通道的横截面100x80微米，交叉流道间的壁厚为20-25 微米。核心结构四周设置有顶板和盖板，并设置有换热器流体进出口管道。这种微型换热器的有效容积通常为1 立方厘米，内表面积为300 平方厘米，换热面积为150平方厘米。这些通道之间和外部都经氦气检验密封性。由于流道尺寸小，结构牢固，可以施加相对较高的操作压力(25bar)。

The core structure of the microheat exchanger consists of about 100 thin sheets, about a few square centimeters in volume, containing rectangular microchannels, stacked laterally and sealed together to form two independent channels of the heat transfer fluid and the process fluid, with about 4,000 microchannels. The cross section of a single microchannel is 100x80 microns, and the wall thickness between the cross channels is 20-25 microns. A top plate and a cover plate are arranged around the core structure, and a heat exchanger fluid inlet and outlet pipe is arranged. The effective volume of this micro heat exchanger is usually 1 cubic centimeter, the internal surface area is 300 square centimeters, and the heat exchange area is 150 square centimeters. These channels are sealed by helium gas between and outside. Due to the small size and strong structure of the runner, relatively high operating pressure (25bar) can be applied.

图5是板式逆流微型换热器的设计原理及流动结构。图6是装配有PEEK壳体和单换热板的逆流微型换热器。

堆叠板换热器中的逆流换热的优势在于，与其他热交换配置相比，从热力学的角度来看，逆流是最有效的。板片与板片之间有平行的肋，形成引导流体的通道，并增加设备的机械稳定性，这对于在高压差下换热非常重要。板片的四角都设有开口，冷热流体的进出口交替分布在其四角开口处。在这种堆叠换热器中传递的总热量是由板片的数量决定的，板片的数量受限于进出口流道的压损。

Figure 5 shows the schematic of the design and flow configuration of a plate-type counterflow micro heat exchanger.

Figure 6 shows the assembled counter-flow micro heat exchanger with PEEK housing and single platelet.

The advantage of counterflow heat exchange in stacked plate devices is that it is the most efficient from a thermodynamic point of view compared to other heat exchange configurations. There are parallel ribs between the plates, forming channels to guide the fluid and increasing the mechanical stability of the device, which is very important for heat transfer at high pressure differences. The four corners of the plate are provided with openings, and the inlet and outlet of the hot and cold fluid are alternately distributed in the four corner openings. The total heat transferred in this stacked heat exchanger is determined by the number of plates, which is limited by the pressure loss of the inlet and outlet channels.

图5 板式逆流微型换热器的设计原理及流动结构

Figure 5 Schematic of the design and flow configuration of a plate-type counterflow micro heat exchanger

图6 装配有PEEK壳体和单换热板的逆流微型换热器

Figure 6 assembled counter-flow micro heat exchanger with PEEK housing and single platelet

图7是部分重叠微通道中不混相流体的传质示意图；图8是部分重叠微通道的截面扫描电子显微照片；图9和图10分别是一种萃取装置的扫描电子显微照片和示意图，本装置在两个流体通道间设置有与流体方向成一定角度的狭缝，用于两个流体之间的交换。

不混相流体之间的交换的优势在于，萃取过程是基于两种不混相流体的接触和两相的传质。小型化导致表面积与体积比的增大，从而导致交换界面的相应增大。可在一定的流量和粘度范围内实现稳定流动。流动的稳定性特别受到表面力的影响，而浮力、动量和粘性等其他参数则无关紧要。通过楔形分流器分离接触流体，可以以高精度进行，并且两相的混合很少。

Figure 7 shows the Schematic of solule exchange between immiscible fluids in partially overlapping microchannels. Figure 8 shows the scanning electron micrograph of the cross section of the partially overlapping microchannels . Figure 9 and Figure 10 shows the scanning electron micrograph and an Schematic of extraction unit. The device is provided with a slit between two fluid channels at a certain Angle to the direction of the fluid for the exchange between the two fluids.

The advantage of the exchange between immiscible fluids is that,Extraction processes considered are based on the contact of two immiscible fluids and solute transfer between the two phases. Miniaturization leads to an increase of surface area to volume ratio, it results in a corresponding enlargement of the exchange interface. Stable flow can be achieved within a certain range of flow rates and viscosities. The stability of the flow is influenced in particular by surface forces, whereas olher parameters sich as buoyancy, momentum,  and viscous are of minor importance. Splitting of the contacting fluids by a wedge-shaped flow divider can be performed with a high precision and only minor mixing of the two phases.

图7 部分重叠微通道中不混相流体的传质示意图

Figure 7 Schematic of solule exchange between immiscible fluids in partially overlapping microchannels

图片文件名称：20231211B-1-文献-UBC-Quak Foo Lee-9

图8 部分重叠微通道的截面扫描电子显微照片

Figure 8 Scanning electron micrograph of the cross section of the partially overlapping microchannels

图9 萃取装置的扫描电子显微照片

Figure 9 Scanning electron micrograph of extraction unit.

图10 萃取装置的扫描电子显微照片

Figure 10 Schematic electron micrograph of extraction unit.

图11是错流过滤器的扫描电子显微照片，该过滤器由与流动方向成一定角度排列的楔形分流器组成。在宏观范围内，过滤和筛结构通常根据开口的形状和位置进行精心设计。在微观范围内，通常采用具有不规则图案的多孔材料。微加工工艺可以通过加工各种原材料来生产规则孔的微过滤器，也可以设计每个孔的大小，形状和位置。典型的微过滤器孔径在微米范围内。特殊结构下可针对含悬浮颗粒的流体设计错流过滤器。膜分离使用时，微通道装置可集成入口和出口的流体。集成式气体膜分离微反应装置可应用于燃料电池领域。

Figure 11 is a scanning electron micrograph of a cross-flow filter consisting of wedge-shaped diverters arranged at an Angle to the direction of flow. On a macro scale, filter and screen structures are often carefully designed according to the shape and position of the opening. At the microscopic scale, porous materials with irregular patterns are commonly used. The micromachining process can produce microfilters with regular holes by processing various raw materials, and the size, shape and position of each hole can also be designed. Typical microfilter apertures are in the micron range. Cross-flow filters can be designed for fluids containing suspended particles in special structures. When membrane separation is used, the microchannel device can integrate the inlet and outlet fluids. The integrated gas membrane separation microreaction device can be used in the field of fuel cell.

图11 错流过滤器的扫描电子显微照片

Figure 11 Scanning electron micrograph of a cross-flow filter.

 江苏航烨能源科技有限公司副总经理宋总表示：“的确，微流体在化学中的潜力已在研究环境中得到广泛证明，并且由于微反应器可以轻松扩展，特别是随着现成的微流体工具变得越来越容易获得和复杂，在工业环境中的使用也越来越多。它们已被证明对危险的化学反应特别有用，这些反应在更大规模下可能变得困难或不可能，但除此之外，还表明大多数化学反应可以使用微流体以更高的效率进行。”