MEASUREMENTS OF HEAT-MASS TRANSFER AND PRESSURE DROP FOR SOME NON-STANDARD ARRAYS OF TUBES IN CROSSFLOW
A concept of tube transformation is introduced to generate a diverse set of new patterns of tube arrangements by shifting rows in transverse direction by an arbitrary offset pitch. Heat transfer and pressure drop for two types of standard arrays (in-line and staggered) and four thus-generated non-standard tube arrays were experimentally investigated. The heat transfer characteristics were deduced from the mass transfer measurements performed via the naphthalene sublimation technique, and by applying the analogy between mass and heat transfer processes. It was found that heat transfer rates and friction factors of the non-standard arrays were dispersed between those of the in-line and staggered arrays. Three types of non-standard arrays have non-uniform heat transfer coefficients in the fully developed regime. For a given amount of heat transfer rate, the per-tube pumping power required to overcome the pressure drop across the tube bank was calculated and compared to each array. The in-line array, the simplest layout, shows a minimum power consumption.