CAJ | 학술논문

可视化实验研究了透明螺旋折流板换热器的壳程速度分布特征，重点研究了轴向速度的分布规律及对应的机理。结果表明，轴向速度按照折流板的螺旋周期呈周期性变化，不同流量下同一测点的轴向速度分布规律相似。轴向速度在换热器壳程周边区域分布比较均匀，沿轴向变化幅度较小，流动相对稳定，湍流度较低。由于受三角区漏流的影响，管束中心区域轴向流速急剧增大，沿轴向变化幅度较大，稳定性差，湍流强度较高。中心区域轴向速度平均值明显高于外围区域，离换热器中心越近，轴向速度越大。随着壳程流量的增大，中心区域轴向速度的增幅高于外围区域。管束中心处轴向速度波动剧烈，壳程流量较小时，中心处轴向流速平均值最大，随着流量的增加，湍流度增大，流体返混现象明显，中心处轴向流速平均值逐渐减小。
가시화실험연구료투명라선절류판환열기적각정속도분포특정，중점연구료축향속도적분포규률급대응적궤리。결과표명，축향속도안조절류판적라선주기정주기성변화，불동류량하동일측점적축향속도분포규률상사。축향속도재환열기각정주변구역분포비교균균，연축향변화폭도교소，류동상대은정，단류도교저。유우수삼각구루류적영향，관속중심구역축향류속급극증대，연축향변화폭도교대，은정성차，단류강도교고。중심구역축향속도평균치명현고우외위구역，리환열기중심월근，축향속도월대。수착각정류량적증대，중심구역축향속도적증폭고우외위구역。관속중심처축향속도파동극렬，각정류량교소시，중심처축향류속평균치최대，수착류량적증가，단류도증대，류체반혼현상명현，중심처축향류속평균치축점감소。
Experimental study was explored with the ultrasonic Doppler velocimeter on the shell side fluid flow characteristics in helical baffled heat exchanger made from acrylic glass. Emphasis was on the axial velocity distribution characteristics. Results indicate that the axial velocity is uniformly distributed in the circumferential region of the shell side. Benefiting from the leakage flow in the triangular region, the corresponding axial velocity in the central region is rapidly increased. With the increase of mass flow rate, the variation magnitude of axial velocity in the central region is much larger than that in the circumferential region. An obvious fluctuation of axial velocity on the shell side of the helical baffled heat exchanger is also an important phenomenon. The mean velocity in the central region increases with the mass flow rate, but this feature is absent when the corresponding turbulent flow is dominant and backmixing flow occurs.