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Purpose: This paper aims to carry out numerical study on growth of a single bubble from a curved hydrophilic surface, in nucleate pool boiling (NPB). The boiling performance associated with NPB on a curved surface has been analyzed in contrast to a plane surface. Design/methodology/approach: Commercial software ANSYS Fluent 2021 R1 has been used with its built-in feature of interface tracking based on volume of fluid method. For water as the working fluid, the effect of microlayer evaporation underneath the bubble base has been included with the help of user-defined function. The phase change behavior at the interface of vapor bubble has been modeled by using "saturated-interface-volume" phase change model. Findings: An interesting outcome of the present study is that the bubble departure gets delayed with increase in curvature of the heating surface. Wall heat flux is found to be higher for a curved surface as compared to a plane surface. Effect of wettability on the time for bubble growth is relatively more for the curved surface as compared to that for a plane surface. Originality/value: Effect of surface curvature has been investigated on bubble dynamics and also on temporal variation of heat flux. In addition, the impact of surface wettability along with the surface curvature has also been analyzed on bubble morphology and spatial variation of heat flux. Furthermore, the influence of wall superheat on the bubble growth and also the wall heat flux has been studied for fixed angle of contact and varying curvature. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to focus on the surface curvature, jet to target spacing and jet Reynolds number effects on the heat transfer and fluid flow characteristics of a slot jet impinging on a confined concave target surface at constant jet to target spacing. Design/methodology/approach: Numerical simulations are used in this research. Jet to target spacing, H/B is varying from 1.0 to 2.2, B is the slot width. The jet Reynolds number, Rej, varies from 8,000 to 40,000, and the surface curvature, R2/B, varies from 4 to 20. Results of the target surface heat transfer, flow parameters and fluid flow in the concave channel are performed. Findings: It is found that an obvious backflow occurs near the upper wall. Both the local and averaged Nusselt numbers considered in the defined region respond positively to the Rej. The surface curvature plays a positive role in increasing the averaged Nusselt number for smaller surface curvature (4-15) but affects little as the surface curvature is large enough (> 15). The thermal performance is larger for smaller surface curvature and changes little as the surface curvature is larger than 15. The jet to target spacing shows a negative effect in heat transfer enhancement and thermal performance. Originality/value: The surface curvature effects are conducted by verifying the concave surface with constant jet size. The flow characteristics are first obtained for the confined impingement cases. Then confined and unconfined slot jet impingements are compared. An ineffective point for surface curvature effects on heat transfer and thermal performance is obtained. [ABSTRACT FROM AUTHOR]

Liquid-filled microchannels are common in biological tissues, such as blood capillaries and neuronal axons, which may often be regarded as cylindrical compressible liquid inclusions embedded in an infinite elastic matrix. How surface effects influence the elastic field and effective mechanical properties of such liquid inclusions remain elusive, especially when the inclusion size is at micro level wherein surface tension plays a significant role. We present first a theoretical model to analyze the elastic field of a cylindrical compressible liquid inclusion, with surface effects duly accounted for. We then use the solutions of our model, together with the Eshelby approach, to estimate the effective mechanical properties of a composite containing sparsely distributed cylindrical liquid inclusions. Different from previous studies, our model accounts for the nonlinear dependence of the normal vector and curvature of a liquid-solid surface upon surface deformation, achieved by expressing both as first order functions of surface displacement. We then linearize the deformation-induced surface curvature to simplify the problem and get the solution using linearized curvature. Predictions of our model demonstrate that surface effects prevent deformation of the liquid inclusion and increase stress concentration around the inclusion. Further, as the surface energy is increased, the effective Young's modulus of the two-phase composite first increases and then decreases, and the transition point is related to the bulk modulus of liquid; when the surface energy becomes sufficiently large, the effective Poisson ratio becomes negative. These results are useful for understanding and exploring the mechanical behaviors of a wide range of liquid-filled porous biological materials which contain distributed cylindrical pores, e.g., blood vessels, neuronal axons, dentinal tubules and hydrogel pores. [ABSTRACT FROM AUTHOR]

We present an effective computer simulation method, called 3D object stochastic kinetic modelling framework (3DO-SKMF), to calculate atomic movements in 3D objects including surface segregation and Gibbs–Thomson effect (surface curvature). Objects with any kind of shapes can easily be considered thanks to the flexibility and versatility of the model and code. Accordingly, the model and the computer code can be used in a wide variety of applications: nanoparticles, nanorods, nanotubes, nanopillars, etc. To increase the versatility of the model, it includes stochastic noise in a tuneable manner. This means that if the noise level is zero, the model is completely deterministic (mean-field), whereas by increasing the noise level the result gets closer and closer to that obtained by a kinetic Monte Carlo calculation. This allows us to calculate processes with activation barriers. Besides demonstrating the capabilities of the model, we also reproduce an experimental result showing decomposition of Ag–Cu nanoparticles. Program title: 3DO-SKMF CPC Library link to program files: http://dx.doi.org/10.17632/776b7txmhv.1 Licensing provisions: CC BY NC 3.0 Programming language: ISO C Nature of problem: Atomistic simulation of nano-objects with free surfaces by calculating occupation probabilities. The model includes surface segregation and Gibbs–Thomson effect (surface curvature). Solution method: Numerical solution of a system of differential equations with taking into account the conservation of matter. The number of equations is equal to the number of lattice sites in a 3D lattice. Additional comments including restrictions and unusual features: The model contains parameters that can be determined from macroscopic measurements, still in the background it follows an atomistic approach. Note that the provided code is written for nanospheres (hollow and solid), nanowires and nanotubes, however objects with any kind of shapes can easily be considered. Due to the flexibility of the code, with minor change of initialization, any 3D object can be simulated. The published code uses the face centred cubic lattice (fcc), its modification for other lattices is, however, straightforward. [ABSTRACT FROM AUTHOR]