Compound heat transfer enhancement of a dimpled tube with a twisted tape swirl generator

Heat transfer and friction characteristics of shell and tube heat exchanger with multi inserted swirl vanes

“…Thianpong et al [7] have investigated experimentally the effect of twisted tape with variable twist ratio, in a dimpled inner pipe of a counter flow double pipe heat exchanger with dimple variable pitch ratio. Heat transfer and friction characteristics of turbulent air flow at a Reynolds number range from 12000 to 44000 are investigated.…”

Air Jet Assisted Machining of Titanium Alloy

“…The air jet from the air nozzle could act as like a turbulence promoter, such as grooves (13) and dimples (14) on a tube wall and twisted tapes in a tube (14) . Turbulence promoters increase the degree of turbulence intensity and friction factor (14) .…”

“…Turbulence promoters increase the degree of turbulence intensity and friction factor (14) . As a result, they can increase Nusselt number and enhance the rate of heat transfer even if the Reynolds number is the same.…”

Comparative Performance Analysis of Different Twisted Tape Inserts in the Absorber Tube of Parabolic Trough Collector

“…They found that heat transfer and pressure drop decrease with increase in free space length. The enhancement in heat transfer rate were obtained by combining several devices with twisted tape inserts in different research work such as corrugated tube [5], conical ring [6], twisted tape with spirally grooved tube [7], dimpled tube [8], twisted tape with wire coil [9] and wire coil tabulators [10]. Chang et al [11] developed a broken twisted tape for mixing the working fluid and compared with smooth twisted tape insert in the tube and found that the heat transfer coefficient, thermal performance factor and mean fanning friction factor enhanced by 1.28-2.4, 0.99-1.8 and 2.0-4.7 times respectively, for Re of 1000-40000.…”