Falling film hydrodynamics and heat transfer under vapor shearing from various orientations
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Tarih
2024
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Aip Publishing
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Vapor shearing is a common issue encountered in the operations of falling film heat exchangers. The vapor stream effect depends on its orientation. This study investigates liquid film hydrodynamics and heat transfer performance under the influence of vapor streams from different orientations. The results indicate that both orientation and velocity of vapor determine the encountering time and position of the films on the tube's two sides. The liquid film thickness uniformity and the liquid column deflection vary significantly depending on the orientation and velocity of the vapor. Zones of accelerated liquid film, climbing liquid film, liquid stagnation, and transition of liquid film flow pattern are observed. The gradient of film thickness along the tube axis and the deflection in time-averaged peripheral film thickness increase as the vapor orientation varies from 0 degrees to 90 degrees and subsequently decrease as the vapor orientation varies from 90 degrees to 180 degrees. Vapor streams have more pronounced effects on time-averaged peripheral film thickness in regions close to the liquid inlet and outlet. Vapor streams result in changes in peripheral heat transfer coefficients toward the downstream side depending on the orientation and velocity of the vapor. The impact of vapor streams on the overall heat transfer coefficient does not directly correlate with the velocity of the vapor when maintaining the same orientation.
Açıklama
Anahtar Kelimeler
Flow, Evaporatıon, Performance, Water, R134a
Kaynak
Physics of Fluids
WoS Q Değeri
N/A
Scopus Q Değeri
Q1
Cilt
36
Sayı
5