[1] Sun Jian, Shi Mingheng,. Numerical study on dehumidifying processin falling film dehumidifier [J]. Journal of Southeast University (English Edition), 2007, 23 (2): 272-277. [doi:10.3969/j.issn.1003-7985.2007.02.024]
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Numerical study on dehumidifying processin falling film dehumidifier(
)
逆流降膜除湿器除湿过程的数值研究
)Journal of Southeast University (English Edition)[ISSN:1003-7985/CN:32-1325/N]
- Volumn:
- 23
- Issue:
- 2007 2
- Page:
- 272-277
- Research Field:
- Chemistry and Chemical Engineering
- Publishing date:
- 2007-06-30
Info
- Title:
- Numerical study on dehumidifying processin falling film dehumidifier
- 逆流降膜除湿器除湿过程的数值研究
- Author(s):
- Sun Jian1; 2; Shi Mingheng1
-
1School of Energy and Environment, Southeast University, Nanjing 210096, China
2Department of Thermal Energy and Power Engineering, Jingdezhen Ceramic Institute, Jingdezhen 333001, China
- Keywords:
- dehumidifier; liquid desiccant; falling film; numerical simulation
- PACS:
- TQ021
- DOI:
- 10.3969/j.issn.1003-7985.2007.02.024
- Abstract:
- A counter flow model of simultaneous heat and mass transfer of a vapor absorption process in a falling film dehumidifier is developed.The governing equations with appropriate boundaries and interfacial conditions describing the dehumidifying process are set up. Calcium chloride is applied as the desiccant.The dehumidifying process between falling liquid desiccant film and process air is analyzed and calculated by the control volume approach.Velocity field, temperature distribution and outlet parameters for both the process air and desiccant solution are obtained.The effects of inlet conditions and vertical wall height on the dehumidification process are also predicted.The results show that the humidity ratio, temperature and mass fraction of salt decrease rapidly at the inlet region but slowly at the outlet region along the vertical wall height.The dehumidification processes can be enhanced by increasing the vertical wall height, desiccant solution flow rates or inlet salt concentration in the desiccant solution, respectively.Similarly, the dehumidification process can be improved by decreasing the inlet humidity ratio or flow rates of the process air.The obtained results can improve the performance of the dehumidifier and provide the theoretical basis for the optimization design, and the operation and modulation of the solar liquid desiccant air-conditioning systems.
- 建立了模拟逆流降膜除湿过程传热传质的数学模型, 给出了传热传质的控制方程和适当的边界条件和气液界面条件.采用氯化钙作为除湿剂, 运用控制容积法对降膜除湿溶液与被处理空气之间的除湿过程进行了分析和计算.获得了相应的除湿溶液与被处理空气的速度场、温度分布和出口参数.计算结果表明:沿着除湿器高度方向溶液和空气的温度、溶液的浓度、空气的湿度在入口区域变化较快而在出口区域变化较慢.可分别通过增加竖壁的高度、溶液的入口浓度和溶液的流速来改善除湿过程;同样, 也可通过降低空气的流速或空气入口湿度达到改善除湿过程的目的.研究结果有利于改进除湿器的性能, 为太阳能液体除湿、空调系统的优化设计和运行调节提供了理论依据.
References:
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[5] Radhwan A M, Gari H N, Elsayed M M.Parametric study of a packed bed dehumidifier/regenerator using CaCl2 liquid desiccant [J]. Renewable Energy, 1993, 3(1):49-60.
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[8] Rahamah A, Elsayed M M, Al-Najem N M.A numerical solution for cooling and dehumidification of air by a falling desiccant film in parallel flow [J].Renewable Energy, 1998, 13(3):305-322.
[9] Saman W Y, Alizadeh S.Modelling and performance analysis of a cross-flow type plate heat exchanger for dehumidification/cooling [J].Solar Energy, 2001, 70(4):361-372.
[10] ASHRAE Handbook.Fundamentals [M].Society of Heating, Refrigeration and Air-Conditioning Engineers, Inc., 1993.
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Memo
- Memo:
- Biographies: Sun Jian(1973—), male, graduate;Shi Mingheng(corresponding author), male, professor, mhshi@seu.edu.cn.