Papers by Marilize Everts
Simultaneous development of the hydrodynamic and thermal boundary layers of mixed convective laminar flow through a horizontal tube with a constant heat flux
International Journal of Thermal Sciences
Development of the hydrodynamic and thermal boundary layers of forced convective laminar flow through a horizontal tube with a constant heat flux
International Journal of Thermal Sciences
Bulletin of the American Physical Society, 2019
to provide a better understanding of the bubble dynamics and heat transfer as these are of great ... more to provide a better understanding of the bubble dynamics and heat transfer as these are of great importance to many industrial and everyday processes. It is proposed that nanoparticle surface coatings may be a simple and scalable method of modifying the surface wettability and structure with the associated differences in bubble-surface interactions and the consequent variations in bubble dynamics, critical heat flux (CHF) and heat transfer coefficient. This work aims to develop an improved understanding of bubble dynamics such as bubble velocity, growth rate, bubble density distribution and detachment frequency on coated microwires at various heat fluxes. Experimental investigations will consider nanoparticle coated and bare platinum microwires with diameters of 100 and 250 micrometres, in pool boiling with water as working fluid. High speed, high resolution videography will be used to observe bubbles from nucleation to departure. The analysis will focus on the bubble dynamics occurring on nanoparticle coated and bare microwires. Bubble dynamics and CHF for the coated surfaces are expected to change compared to the bare wire depending on the nature of the surface coating applied.
Experimental Thermal and Fluid Science, 2019
Influence of inlet contraction ratios on the heat transfer and pressure drop characteristics of s... more Influence of inlet contraction ratios on the heat transfer and pressure drop characteristics of single-phase flow in smooth circular tubes in the transitional flow regime,
The effects of surface roughness on fully developed laminar and transitional flow friction factors and heat transfer coefficients in horizontal circular tubes
International Journal of Heat and Mass Transfer, 2022
Single-phase mixed convective heat transfer and pressure drop in the laminar and transitional flow regimes in smooth inclined tubes heated at a constant heat flux
Experimental Thermal and Fluid Science, 2019
Abstract Heat transfer and pressure drop experiments were conducted in the laminar and transition... more Abstract Heat transfer and pressure drop experiments were conducted in the laminar and transitional flow regimes at different inclination Grashof numbers that generated different levels of buoyancy. A wide range of Grashof numbers were covered by varying both the inclination angle and heat flux. The experiments were conducted on an experimental set-up on which flow could occur through a smooth tube positioned at different inclination angles, from vertical downward (−90°) flow to vertical upward (+90°) flow. The test section had an internal diameter of 5.1 mm, length of 4.6 m and a square-edged inlet was used. The experiments were conducted at different inclination angles between Reynolds numbers of 1000 and 6000 at heat fluxes of 4–8 kW/m2. The test fluid was water and the Prandtl numbers varied from 3 to 7. It was found that an increase in the inclination angle from horizontal flow (0°) to vertical (±90°) flow, decreased the buoyancy effects which led to decreased laminar heat transfer coefficients and friction factors for both upward and downward flows. The onset of buoyancy effects was significant near the vertical inclinations and caused a rapid increase in the laminar heat transfer coefficients and friction factors when the inclination angles moved from vertical to horizontal orientations. An inclined tube Grashof number which is a function of inclination angle was defined and used to express the laminar Nusselt numbers as a forced convection part plus an enhancement component owing to mixed convection. The laminar friction factors were expressed as a function of forced convection/isothermal part multiplied by the mixed convection part. Furthermore, it was found that the critical Reynolds numbers at which transition started increased as the inclination angles increased from horizontal to vertical, while the end of transition were inclination angle independent. This caused the width of the transitional flow regime to decrease, as well as the transition gradients to increase, with increasing inclination angle at different heat fluxes. It was also found that the flow directions (upward and downward) had a negligible effect on the heat transfer coefficients and friction factors in the entire transition and quasi-turbulent regions.
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Papers by Marilize Everts