PERFORMANCE IMPROVEMENT OF DOUBLE PIPE HEAT EXCHANGER BY USING TURBULATOR
The various techniques for achieving improved heat transfer are usually referred to as “heat transfer augmentation” or “heat transfer enhancement” and the heat exchanger provided with heat transfer enhancement techniques as “Augmented Heat Exchanger”. The objective is to reduce as many of the factors as possible: Capital Cost, Power Cost, Maintenance Cost, Space and Weight, Consistent with safety and reliability. Present work describes the principal techniques of industrial importance for the augmentation of single phase heat transfer on the inside of tubes namely twisted tapes. So twisted tape should be used in heat exchanger when high heat transfer rate is required and pressure drop is of no significance.
Heat Transfer Enhancement in Concentric Tube Heat Exchanger in ANSYS FLUENT
The study deals with CFD simulation of concentric tube heat exchanger and concentric tube heat exchanger with insert used for heating air using ANSYS FLUENT Software for steel. Design process for heat exchanger and insert has been carried out in SOLIDWORKS, fluid domain is formed in ANSYS workbench, followed by meshing in default mesh tool of ANSYS and solution is developed using ANSYS FLUENT software as FINITE ELEMENT TOOL and the results are compared between the two designs for parallel flow. The Reynolds number of air varied from 21000 to 100000. Inlet temperature of hot water and cold air are 60 C and 26 C respectively. The work included the determination of Nusselt number, heat transfer coefficient and pressure drop for insert in parallel flow.
Prediction of friction factors and heat transfer coefficients for turbulent flow in corrugated tubes combined with twisted tape inserts. Part 2: heat transfer coefficients
Abstract A simple mathematical model following the suggestion of Smithberg and Landis has been created to predict the heat transfer coefficients for the case of a fully developed turbulent flow in a spirally corrugated tube combined with a twisted tape insert. The heat transfer can be predicted from the combined effects of the axial and the tangential boundary layer flows coupled with an additional “vortex mixing” effect near the wall through the solution of the corresponding momentun and energy transfer equations. The “wall roughness” has an effect simultaneously on the axial velocity, secondary fluid motion and the resulting swirl mixing. The model reflects the influence of the “wall roughness” and the twisted tape on the thermal resistances of the helicoidal core flow, twisting boundary layer flow and the viscous sublayer near the wall. The calculated heat transfer coefficients have been compared to 544 experimental points obtained from 57 tubes tested. Four hundred thirty-eight points (80.5%) have a relative difference of less than ±15% and 106 points (19.5%) have a relative difference between ±(15–20)%.