A high-aspect-ratio microchannel heat exchanger based on multi-tool milling process was developed. Several slotting cutters were stacked together for simultaneously machining several high-aspect-ratio microchannels wi...A high-aspect-ratio microchannel heat exchanger based on multi-tool milling process was developed. Several slotting cutters were stacked together for simultaneously machining several high-aspect-ratio microchannels with manifold structures. On the basis of multi-tool milling process, the structural design of the manifold side height, microchannel length, width, number, and interval were analyzed. The heat transfer performances of high-aspect-ratio microchannel heat exchangers with two different manifolds were investigated by experiments, and the influencing factors were analyzed. The results indicate that the magnitude of heat transfer area per unit volume dominates the heat transfer performances of plate-type micro heat exchanger, while the velocity distribution between microchannels has little effects on the heat transfer performances.展开更多
设计了一种基于机器视觉的焊接缺陷自动检测方法,用于实现板式换热器接头焊缝的无损检测。根据接头焊缝缺陷圆周分布的特点,设计了三相机采集平台,并提出了针对圆弧形ROI区域的提取-展开-检测(Extract-Unwrap-Detect,EUD)的检测策略。...设计了一种基于机器视觉的焊接缺陷自动检测方法,用于实现板式换热器接头焊缝的无损检测。根据接头焊缝缺陷圆周分布的特点,设计了三相机采集平台,并提出了针对圆弧形ROI区域的提取-展开-检测(Extract-Unwrap-Detect,EUD)的检测策略。首先使用改进的ORB(Oriented FAST and Rotated BRIEF)匹配算法定位并提取圆弧形ROI区域;然后引入圆弧展开算法将旋转目标检测转变为水平目标检测,降低检测难度同时提高目标检测精度;最后使用YOLOv5精确定位预测目标框的位置再将其映射回原图像。实验结果表明:EUD方法在验证集的mAP_(0.5)达到98.6%,较基于YOLOv5、RCNN的旋转目标检测模型分别提高了14.2%与16.2%;在测试集上EUD准确率达到96.9%,单张图片的检测时间小于300 ms,能够满足实际生产需求。展开更多
基金Projects(50675070 50805052) supported by the National Nature Science Foundation of China+1 种基金Projects(07118064 8451064101000320) supported by the Natural Science Foundation of Guangdong Province
文摘A high-aspect-ratio microchannel heat exchanger based on multi-tool milling process was developed. Several slotting cutters were stacked together for simultaneously machining several high-aspect-ratio microchannels with manifold structures. On the basis of multi-tool milling process, the structural design of the manifold side height, microchannel length, width, number, and interval were analyzed. The heat transfer performances of high-aspect-ratio microchannel heat exchangers with two different manifolds were investigated by experiments, and the influencing factors were analyzed. The results indicate that the magnitude of heat transfer area per unit volume dominates the heat transfer performances of plate-type micro heat exchanger, while the velocity distribution between microchannels has little effects on the heat transfer performances.
文摘基于产品碳足迹量化的要求和指南,结合生命周期评价法,构建了板式热交换器的碳足迹核算框架,计算了不同型号尺寸板式热交换器在生产生命周期内各阶段的碳足迹。结果表明:A、B、C、D 4种型号板式热交换器在整个生产生命周期的碳排放量分别为1.0731,3.9108,6.5001,29.2184 t CO_(2)e;板片传热面积的增幅与碳排放活动水平的增幅接近,是影响碳排放活动的重要因素;热交换器整机尺寸与碳排放量成正相关性,尺寸最大的D型的整机制造碳排放量约是尺寸最小的A型的27倍;A、B、C、D 4种型号材料获取阶段的碳排放量在整个生产生命周期的占比分别为95.00%、98.61%、98.83%和98.73%,材料消耗是板式热交换器制造过程中的主要碳排放来源。
文摘设计了一种基于机器视觉的焊接缺陷自动检测方法,用于实现板式换热器接头焊缝的无损检测。根据接头焊缝缺陷圆周分布的特点,设计了三相机采集平台,并提出了针对圆弧形ROI区域的提取-展开-检测(Extract-Unwrap-Detect,EUD)的检测策略。首先使用改进的ORB(Oriented FAST and Rotated BRIEF)匹配算法定位并提取圆弧形ROI区域;然后引入圆弧展开算法将旋转目标检测转变为水平目标检测,降低检测难度同时提高目标检测精度;最后使用YOLOv5精确定位预测目标框的位置再将其映射回原图像。实验结果表明:EUD方法在验证集的mAP_(0.5)达到98.6%,较基于YOLOv5、RCNN的旋转目标检测模型分别提高了14.2%与16.2%;在测试集上EUD准确率达到96.9%,单张图片的检测时间小于300 ms,能够满足实际生产需求。
