An Experimental and Numerical Study of Heat Transfer and Flow Characteristics of Laminar Flow in a Circular Tube With Wedge-Shaped Wavy-Tape Inserts

2018 ◽  
Author(s):  
Yunmin Liang ◽  
Peng Liu ◽  
Nianben Zheng ◽  
Feng Shan ◽  
Zhichun Liu ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Heat Transfer Enhancement ◽  
Circular Tube ◽  
Flow Characteristics ◽  
Stereoscopic Particle Image Velocimetry ◽  
Flow Structures ◽  
Enhancement Ratio ◽  
Transfer Enhancement ◽  
Piv Measurements

In this study, a new type of tube inserts, named wedge-shaped wavy-tape insert, which is designed from bionics based on the movement of cuttlefish, is reported. The numerical simulation was carried out to investigate the effects of wedge-shaped wavy-tape insert arrangements on the heat transfer and flow characteristics of laminar flow in a circular tube under constant heat flux conditions. Details of the flow structures in the circular tube with wedge-shaped wavy-tape inserts which are arranged in same phase (S-type wavy tape) and different phase (D-type wavy tape) were presented and analyzed respectively. Then stereoscopic particle image velocimetry (Stereo-PIV) measurements on the flow structures were conducted to verify the numerical results. The flow structures obtained through simulations and PIV measurements agree well. It was observed that the arrangements of wedge-shaped wavy-tape inserts have a significant influence on the thermo-hydraulic performance. The average friction factor enhancement ratio f/f0 of D-type wavy tape were about 14%–20% lower than S-type wavy tape, but average heat transfer enhancement ratio Nu/Nu0 of D-type wavy tape were about 7%–14% higher than S-type wavy tape. The best performance evaluation criterion of D-type wavy tape could be improved to 3.02. The result shown the wedge-shaped wavy-tape insert is a promising technique for laminar convective heat transfer enhancement.

scholarly journals Heat Transfer Enhancement of Laminar Flow in a Circular Tube Using Swirl/Vortex Generator

2014 ◽  
Vol 26 ◽  
pp. 63-68
Author(s):  
Sami D. Salman ◽  
Abdul Amir H. Kadhum ◽  
Mohd S. Takriff ◽  
Abu Bakar Mohamad
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Heat Transfer Enhancement ◽  
Circular Tube ◽  
Vortex Generator ◽  
Transfer Enhancement

scholarly journals CFD study of heat transfer enhancement and fluid flow characteristics of laminar flow through tube with helical screw tape insert

2019 ◽  
Vol 160 ◽  
pp. 699-706 ◽  
Author(s):  
Mehedi Tusar ◽  
Kazi Ahmed ◽  
Muhammad Bhuiya ◽  
Palash Bhowmik ◽  
Mohammad Rasul ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Laminar Flow ◽  
Heat Transfer Enhancement ◽  
Flow Characteristics ◽  
Transfer Enhancement ◽  
Flow Through ◽  
Fluid Flow Characteristics

Study of the boundary layer heat transfer of nanofluids over a stretching sheet: Passive control of nanoparticles at the surface

2015 ◽  
Vol 93 (7) ◽  
pp. 725-733 ◽  
Author(s):  
M. Ghalambaz ◽  
E. Izadpanahi ◽  
A. Noghrehabadi ◽  
A. Chamkha
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Boundary Layer ◽  
Nusselt Number ◽  
Heat Transfer Enhancement ◽  
Base Fluid ◽  
Stretching Sheet ◽  
Volume Fraction ◽  
Enhancement Ratio ◽  
Transfer Enhancement

The boundary layer heat and mass transfer of nanofluids over an isothermal stretching sheet is analyzed using a drift-flux model. The relative slip velocity between the nanoparticles and the base fluid is taken into account. The nanoparticles’ volume fractions at the surface of the sheet are considered to be adjusted passively. The thermal conductivity and the dynamic viscosity of the nanofluid are considered as functions of the local volume fraction of the nanoparticles. A non-dimensional parameter, heat transfer enhancement ratio, is introduced, which shows the alteration of the thermal convective coefficient of the nanofluid compared to the base fluid. The governing partial differential equations are reduced into a set of nonlinear ordinary differential equations using appropriate similarity transformations and then solved numerically using the fourth-order Runge–Kutta and Newton–Raphson methods along with the shooting technique. The effects of six non-dimensional parameters, namely, the Prandtl number of the base fluid Prbf, Lewis number Le, Brownian motion parameter Nb, thermophoresis parameter Nt, variable thermal conductivity parameter Nc and the variable viscosity parameter Nv, on the velocity, temperature, and concentration profiles as well as the reduced Nusselt number and the enhancement ratio are investigated. Finally, case studies for Al2O3 and Cu nanoparticles dispersed in water are performed. It is found that increases in the ambient values of the nanoparticles volume fraction cause decreases in both the dimensionless shear stress f″(0) and the reduced Nusselt number Nur. Furthermore, an augmentation of the ambient value of the volume fraction of nanoparticles results in an increase the heat transfer enhancement ratio hnf/hbf. Therefore, using nanoparticles produces heat transfer enhancement from the sheet.

Heat Transfer in Internal Flows of Non-Linear Fluids: A Review

2006 ◽  
Author(s):  
Dennis A. Siginer ◽  
Mario F. Letelier
Keyword(s):  
Heat Transfer ◽  
Laminar Flow ◽  
Heat Transfer Enhancement ◽  
Polymer Solutions ◽  
Single Mode ◽  
Secondary Flows ◽  
Transfer Enhancement ◽  
Experimental Heat ◽  
Aqueous Polymer ◽  
Non Linear

A survey of the developments in heat transfer studies of non-linear inelastic as well as elastic fluids in tubes is given. Experimental findings concerning heat transfer enhancement characteristics of viscoelastic aqueous polymer solutions are very significant. Specifically, it is reported that heat transfer results for viscoelastic aqueous polymer solutions are drastically higher than those found for water in laminar flow in rectangular ducts. A number of investigators suggested that the high experimental heat transfer values were due to secondary flows resulting from the elasticity of the fluids. In this context recent results concerning the fully developed thermal field in constant pressure gradient driven laminar flow of a class of viscoelastic fluids characterized by single mode, non-affine constitutive equations in straight pipes of arbitrary contour ∂D is reviewed. Heat transfer enhancement due to shear-thinning is identified together with the enhancement due to the inherent elasticity of the fluid. The latter is the result of secondary flows in the cross-section. Increasingly large enhancements are computed with increasing elasticity of the fluid as compared to its Newtonian counterpart. Large enhancements are possible even with dilute fluids. Isotherms for the temperature field are presented and discussed for several non-circular contours such as the ellipse and the equilateral triangle together with heat transfer behavior in terms of the Nusselt number Nu.

Sign in / Sign up

Export Citation Format

Share Document