Hits:

Indexed by:期刊论文

Date of Publication:2016-05-02

Journal:DESALINATION AND WATER TREATMENT

Included Journals:SCIE、Scopus

Volume:57

Issue:21

Page Number:9993-10002

ISSN No.:1944-3994

Key Words:Tube arrangement; Seawater; Overall heat transfer coefficient; Horizontal-tube falling film; Desalination

Abstract:In this paper, two sets of experimental devices have been established for studying the falling film evaporation outside a horizontal tube and condensation inside a horizontal tube, with three different tube arrangements and seawater as the experimental fluid. The rules of the overall heat transfer coefficient (K) are determined by changing saturation temperature (T), Reynolds number (Re), total temperature difference (Delta T), inlet steam velocity (v(s)), and vapor quality (x). Experimental results indicate that the overall heat transfer coefficient of the rotated square arrangement (K-rs) is higher than that of the triangular arrangement (K-t), and the square one (K-s) is the lowest with less impact on Re, T, Delta T, v(s), or x changing. With Re increasing, the K increases first and then declines, especially when Re>Re-cr, K-rs and K-t are almost the same. The increment of T and Delta T leads to the decreasing of the K, while v(s) has little effect on the K. The growth of x contributes a lot to the increment of the K. In the evaporator, the vapor quality contributes a lot in the horizontal direction, while Re is more influential in the vertical direction.