Investigation of the evaporation process of falling film outside a horizontal tube using diode laser absorption spectroscopy

doi:10.7523/j.issn.2095-6134.2020.02.018

Abstract

Abstract: Liquid film flow widely exists in various industrial processes. High-precision measurement of various parameters in the process of liquid film flow is crucial to understand relevant processes and heat transfer mechanisms. Diode laser absorption spectroscopy (DLAS) is used to determine liquid film thickness of the falling film outside horizontal tube. The heat transfer coefficient of the liquid film is calculated by using the tube-wall temperature and the liquid-film temperature. The relationships between liquid film thickness and heat transfer coefficient under different conditions, including spray density (0.16/0.24/0.32 kg (m·s)^-1) and hot water temperature at the inlet of the tube (40/50/60℃), are analyzed. The results show that the average thickness of the liquid film increases with the spray density. The heat transfer coefficient of the liquid film increases with the spray density. When the spray density increases, the heat transfer coefficient of the liquid film increases with the increase of film thickness. When the temperature increases, the liquid film thickness remains constant while the heat transfer coefficient increases.

Key words: measurement, diode laser absorption spectroscopy, falling film, thickness, heat transfer coefficient

CLC Number:

O433.1

QIAO Wenyou, JIANG Yong, YANG Huinan, LI Ling, SU Mingxu, CAI Xiaoshu. Investigation of the evaporation process of falling film outside a horizontal tube using diode laser absorption spectroscopy[J]. , 2020, 37(2): 268-273.

References

[1] 齐鲁山,马虎根,李长生,等. 水平管外降膜蒸发传热性能实验研究[J]. 上海理工大学学报,2010,32(1):27-30.
[2] Hou H,Bi Q,Ma H,et al. Distribution characteristics of falling film thickness around a horizontal tube[J]. Desalination,2012,285(3):393-398.
[3] 欧阳新萍,邱雪松,姜帆. 水平管外R404A降膜蒸发传热的实验研究[J]. 制冷学报,2014,35(1):77-81.
[4] 宋建,韦胜杰,于意奇,等. 竖直平板上电容法测量水膜厚度方法评价[J]. 计量技术,2011(9):15-18.
[5] 王文武,李春国,王新军,等. 金属表面流动液膜厚度的电导法测量技术研究[J]. 东方汽轮机,2010(1):21-25.
[6] 郭斌,李会雄,郭笃鹏. 水平管外降膜流动液膜厚度的测量及分析[J]. 工程热物理学报,2011,32(1):71-74.
[7] 阎维平,李洪涛,叶学民,等. 垂直自由下降液膜厚度的瞬时无接触测量研究[J]. 热能动力工程,2007,22(4):380-384.
[8] 盛伟,李洪涛. 数字图像技术在液膜厚度测量中的应用[J]. 东北电力技术,2007,28(2):44-47.
[9] Hulburt E T,Newell T A. Optical measurement of liquid film thickness and wave velocity in liquid flows[J]. Experiments in Fluids,1996,21(5):357-362.
[10] Módis K,Ger D,Erdélyi K,et al. Measurement of water film thickness by laser-induced fluorescence and Raman imaging[J]. Applied Physics B,2011,102(1):123-132.
[11] 杨斌,潘科玮,杨荟楠,等. 波长扫描直接吸收光谱法燃烧诊断技术适用情况讨论[J]. 上海理工大学学报,2015(5):445-449.
[12] Pan R,Brocksieper C,Jeffries J B,et al. Diode laser-based standoff absorption measurement of water film thickness in retro-reflection[J]. Applied Physics B,2016,122(9):249.
[13] Yang H,Greszik D,Wlokas I,et al. Tunable diode laser absorption sensor for the simultaneous measurement of water film thickness,liquid-and vapor-phase temperature[J]. Applied Physics B,2011,104(1):21-27.
[14] 石建伟,吴威,杨荟楠,等. 基于激光光谱法的尿素水溶液液膜多参数测量[J]. 化工学报,2017,68(1):79-86.
[15] Yang H,Wei W,Su M,et al. Measurement of liquid water film thickness on opaque surface with diode laser absorption spectroscopy[J]. Flow Measurement & Instrumentation,2018,60:110-114.
[16] Moalem-Maron D,Sideman S. Theoretical analysis of a horizontal condenser-evaporator tube[J]. International Journal of Heat & Mass Transfer,1976,19(3):259-270.
[17] Sarma P k,Saibabu J. Evaporation of laminar,falling liquid film on a horizontal cylinder[J]. Wärme-und Stoffübertragung,1992,27:347-355.
[18] Zhang L,Yang S,Xu H. Experimental study on condensation heat transfer characteristics of steam on horizontal twisted ellipticaltubes[J]. Applied Energy,2012,97:881-887.
[19] Putilin J V,Podberezny V L,Rifert V G. Evaporation heat transfer in liquid films flowing down horizontal smooth and longitudinally profiled tubes[J]. Desalination,1996,105:65-170.
[20] 杨洛鹏,邹振宇,李红有.水平管外降膜蒸发传热特性的数值模拟[J].热能动力工程,2017,32(10):24-28,138-139.
[21] Liu Z H, Zhu Q Z,Chen Y M. Evaporation heat transfer of falling water film on a horizontal tube bundle[J]. Heat Trans Asian Res,2002,31(1):42-55.
[22] 陈自刚,王书冯,来盛旺,等.水平管外降膜传热性能的数值模拟及实验研究[J].化工机械,2018,45(6):757-763.
[23] 杨世铭,陶文铨. 传热学[M]. 北京:高等教育出版社,1998.
[24] Hale G M,Querry M R. Optical constants of water in the 200-nm to 200-μm wavelength region[J]. Appl Opt,1973,12:555-563.
[25] Yang H,Greszik D,Dreier T,et al. Simultaneous measurement of liquid water film thickness and vapor temperature using near-infrared tunable diode laser spectroscopy[J]. Applied Physics B,2010,99(3):385-390.