Comparison of one-dimensional and two-dimensional models for wet-surface ®n eciency of a plate-®n-tube heat exchanger S.Y. Liang, T.N. Wong*, G.K. Nathan School of Mechanical and Production Engineering, Nanyang Technological University, Singapore 639798, Singapore Received 12 April 1999; accepted 4 September 1999 Abstract This paper investigates the wet-surface ®n eciency of a plate-®n-tube heat exchanger. Depending on the compromise made between accuracy and complexity, a one-dimensional analytical model, a one- dimensional numerical model and a two-dimensional numerical model are proposed respectively for ®n eciency together with the corresponding computation algorithms. The one-dimensional numerical model considers the local mass transfer eect. The two-dimensional model takes into account of the complex ®n geometry and the variation of moist air properties over the ®n. In the analytical model, two parameters M  and T  a are employed in the solution in place of the C parameter that is commonly used in the literature. A quantitative comparison of these models together with a widely used method by McQuiston is presented. Meanwhile, the ®n performance of a plate-®n-tube heat exchanger is investigated under a variety of ®n geometric parameters and air¯ow conditions, especially for a wide range of air relative humidity (from 20 to 95%). Due to the dierent simpli®cations made in each model, the dierences among the calculation results are found to be signi®cant. Finally, the applications and limitations of these models are discussed along with the error analysis. 7 2000 Elsevier Science Ltd. All rights reserved. Keywords: Fin eciency; Plate-®n-tube; Partially wet; Totally wet; Analytical model; Numerical model Applied Thermal Engineering 20 (2000) 941±962 1359-4311/00/$ - see front matter 7 2000 Elsevier Science Ltd. All rights reserved. PII: S1359-4311(99)00078-2 www.elsevier.com/locate/apthermeng * Corresponding author. Tel.: +65-7995587; fax: +65-7911859. E-mail address: mtnwong@ntu.edu.sg (T.N. Wong).