Brownian Heat Transfer Enhancement in the Turbulent Regime

Abstract

The paper presents convection heat transfer of a turbulent flow Al2O3/water nanofluid in a circular duct. The duct is a under constant and uniform heat flux. The paper computationally investigates the system’s thermal behavior in a wide range of Reynolds number and also volume concentration up to 6%. To obtain the nanofluid thermophysical properties, the Hamilton-Crosser model along with the Brownian motion effect are utilized. Then the thermal performance of the system with the nanofluid is compared to the conventional systems which use water as the working fluid. The results indicate that the use of nanofluid of 6% improves the heat transfer rate up to 36.8% with respect to pure water. Therefore, using the Al2O3/water nanofluid instead of water can be a great choice when better heat transfer is needed.

Discussion of “Accurate and Efficient Explicit Approximations of the Colebrook Flow Friction Equation Based on the Wright ω-Function” by DejanBrkić; and Pavel Praks, Mathematics 2019, 7, 34; doi:10.3390/math7010034

“…Several researchers tried to propose an exact solution of the Colebrook-White equation (which is relevant only for turbulent flow [1,7])with the hope of achieving zero-percent (0%) maximum deviation as proposed in similar research [8][9][10], however simple formulas are always be preferred for highly computationally efficient [1,3]. The authors have presented an interesting work where the Right ω-function and the Padé approximation were used.…”

Unified Friction Formulation from Laminar to Fully Rough Turbulent Flow

“…(1), will be here shown in more details; Here we present friction factors for -laminar, -smooth turbulent flow, and -fully developed rough turbulent flow hydraulic regimes. Turbulent flow is a phenomena that still causes a stir among experts [29,30]. Thus, the here shown relation is suitable for flow of Newtonian fluids, whereas some restrictions are applied for gases [31].…”

Choosing the Optimal Multi-Point Iterative Method for the Colebrook Flow Friction Equation

“…This is of a great significance in computing of flow through miscellaneous pipe-networks of various applications (water, natural gas, air, etc. ), in which multiple evaluations of friction factors take place and when certain cases require only rough estimations; while other very accurate computational models need to be compared, repeated, or analyzed in detail [69][70][71].…”