Experimental investigation on heat transfer performances in half-cylindrical shell space of different heat exchangers. (15th June 2022)

• Record Type: Journal Article
• Authors: Su, Jindong; Chen, Yaping; Wu, Jiafeng; Fei, Fengfan; Yang, Shifan; Gu, Huaduo
• Is Part Of: International journal of heat and mass transfer. Volume 189(2022)
• Publication Date: 2022-06-15
• Subjects: Half-cylindrical space heat exchanger -- Ladder type helical baffles -- Orifice baffles -- Performance experiment -- Heat transfer coefficient -- Comprehensive index; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2022.122684
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlight: The power plant feedwater heaters and the countercurrent U-tube heat exchangers all involve half-cylindrical shell space. Half-cylindrical space heat exchangers with ladder helical, orifice and segmental baffles were experimentally investigated. The ladder helical baffle scheme has superior heat transfer coefficient and comprehensive index than those of the other ones. The orifice baffle scheme has higher comprehensive index but lower heat transfer coefficient than those of segmental ones. The average values of h o Δ p o −1/3 of ladder helical and orifice baffle schemes are about 15% higher than that of segmental one. Abstract: The superheated steam cooling section and the condensate cooling section of the power plant feedwater heaters and the countercurrent U-tube heat exchangers all involve heat transfer in half-cylindrical shell space. The overall and shell-side heat transfer coefficients (h.t.cs.), pressure drop, and the comprehensive performances of some half-cylindrical space heat exchangers with different baffle structures were experimentally investigated. The investigated structures include three ladder helical baffle types [single inclined ladder helical (SH), dual inclined ladder helical (DH) and folded ladder helical (FH)], three orifice baffle types [fillet triangle orifice (F), trefoil-orifice (T) and quatrefoil-orifice (Q)], and segmental baffles (S), and all schemes are of two baffle pitches. Under the same baffle pitch and working condition, the experimental results show that the shell-side h.t.cs. of the ladder helical baffle schemes are higher than those of the orifice baffle schemes and segmental baffle ones; and the shell-side pressure drops of the orifice baffle schemes are much lower than those of the ladder helical baffle schemes and the segmental ones. The values of average comprehensive index h o Δ p o −1/3 of the ladder helical schemes FH-40, DH-40 and the orifice baffle schemes F-40 and T-40 are respectively 14.26%, 17.58%, 15.62% and 12.82% higher than that of the segmental scheme S-40.