Showing papers on "Subcooling published in 2017"
TL;DR: In this article, a stable and efficient jumping droplet condensation on a superhydrophobic surface with three-dimensional (3D) copper nanowire networks was demonstrated for the first time.
178 citations
TL;DR: In this paper, the authors demonstrate enhanced condensation heat transfer on a nanowired hydrophobic copper surface where molecular permeation of water vapor into the separations between nanowires is greatly decreased, rendering spatial control on droplet nucleation and wetting dynamics.
174 citations
TL;DR: This work presents a novel strategy to manipulate droplet behaviors during the process from the droplet nucleation to growth and departure through a combination of spatially controlling initial nucleation for mobile droplets by closely spaced nanowires and promoting the spontaneous outward movement of droplets for rapid removal using micropatterned nanowire arrays.
Abstract: Self-propelled droplet jumping on nanostructured superhydrophobic surfaces is of interest for a variety of industrial applications including self-cleaning, water harvesting, power generation, and thermal management systems. However, the uncontrolled nucleation-induced Wenzel state of condensed droplets at large surface subcooling (high heat flux) leads to the formation of unwanted large pinned droplets, which results in the flooding phenomenon and greatly degrades the heat transfer performance. In this work, we present a novel strategy to manipulate droplet behaviors during the process from the droplet nucleation to growth and departure through a combination of spatially controlling initial nucleation for mobile droplets by closely spaced nanowires and promoting the spontaneous outward movement of droplets for rapid removal using micropatterned nanowire arrays. Through the optical visualization experiments and heat transfer tests, we demonstrate greatly improved condensation heat transfer characteristics ...
101 citations
TL;DR: In this article, a parametric study was conducted to experimentally determine the influence of (β/α) ratios on the heat transfer performance and droplet dynamic under saturation condition near the atmosphere pressure with the presence of non-condensable gases (air).
84 citations
TL;DR: In this article, an original subcooled flow boiling modeling framework for computational fluid dynamics (CFD) is presented, which aims at consistently and accurately characterizing the key physics that affect heat transfer at the boiling surface.
73 citations
TL;DR: In this article, a heat-driven absorption-compression refrigeration system is proposed to produce the cooling energy required to reach a temperature as low as −60 ˚ c. The system utilizes the heat source using a cascade approach.
71 citations
TL;DR: In this article, a transcritical CO2 refrigeration cycle combined with a thermoelectric (TE) subcooler and an expander (TES+EXPHM and TES+EXPML) is proposed.
71 citations
TL;DR: In this paper, an analytical technique is proposed to calculate the growth rate and departure diameter of a nucleating bubble in subcooled flow boiling, where both force and energy balance approaches have been applied.
66 citations
TL;DR: In this paper, heat transfer on super-hydrophobic Si nanowire (SiNW) array-coated surface was investigated and it was shown that SHB surface could have a superior heat and mass transfer performance than hydrophobic surface provided that the liquid droplets on the SHB could be shed away efficiently.
60 citations
TL;DR: In this article, a new ammonia-water cogeneration system is proposed to produce power and refrigeration outputs simultaneously, which combines Kalina power cycle and ejector refrigeration cycle.
59 citations
TL;DR: In this paper, an experiment based on enthalpy difference method and thermal imaging is conducted on a CO2 loop thermosyphon with micro-channel parallel-flow evaporator and condenser.
TL;DR: In this paper, a microgrooved surfaces with reentrant cavities (MSRCs) were fabricated on pure copper substrates by employing the orthogonal ploughing/extrusion (P/E) method.
TL;DR: In this paper, a methodology for modeling two-phase flow distributions in parallel-channel systems is developed, which combines a pressure-drop model for individual parallel channels with a pump curve into a system flow network.
TL;DR: In this paper, the authors extended the Rensselaer polytechnic Institute (RPI) wall boiling model to ultra-high pressure conditions up to 15 MPa and compared the results with the experiments of Bartolemei et al. (1967, 1982).
TL;DR: In this article, a multi-component/multi-phase (MCMP) lattice Boltzmann method with vapor/liquid phase change is proposed for forced condensing flow on a horizontal cold plate at constant wall temperature in the presence of non-condensable gas (NCG).
TL;DR: In this paper, the departure diameter and frequency of bubble departure were measured using high speed visualization experiments with sub-cooled demineralized water at atmospheric pressure for nucleate pool boiling conditions.
TL;DR: In this paper, a multidimensional model of solidification with supercooling and heat transfer is presented, which encompasses all possible stages of the process, namely, single phase liquid cooling from the initial state to the nucleation temperature, kinetic nucleation accompanied by a rapid temperature rise to the nominal phase-change temperature, regular solidification and finally cooling of the solid phase.
TL;DR: In this article, the phase change lattice Boltzmann method was used to simulate the transition from dropwise to filmwise condensation of a dry saturated vapor on downward-facing smooth subcooled horizontal hydrophobic walls with hydrophilic spots.
TL;DR: In this article, a mixture model is applied to study the subcooled boiling of Alumina-water nanofluid in both vertical concentric annulus and vertical tube.
TL;DR: In this article, an open microchannel structure was proposed to reduce the impact of the flow boiling instabilities in open microchannels using deionized water and the results showed that the flow regimes in the open micro-channels differ from those in closed micro channels with stratified flow and no flow instability two types of confined bubbles were observed with characterizations of the effects of the bubbles on each other
TL;DR: In this paper, a semi-analytical method, called the non-continuous Trefftz method, was used to calculate the heat transfer coefficients between the heating surface and the boiling liquid flowing through 1-mm deep minichannel.
Abstract: The paper presents an application of the semi-analytical method, called the non-continuous Trefftz method, to the calculation of the heat transfer coefficients. It is very effective method for solving direct and inverse problems. The results obtained by this method are consistent with the results obtained by using complicated methods: the FEM and Beck method. Sought local heat transfer coefficients between the heating surface and the boiling liquid flowing through 1 mm deep minichannel were calculated from the Robin boundary condition. The temperature of the heating surface and the derivative of the temperature were was found from solving the inverse problem. The study is limited to the identification of the heat transfer coefficient in the subcooled and the saturated nucleate boiling regions. The article presents also the measurement stand and methodology of conducting the experiment. Presented issues allows verification of state-of-the-art methods of solving the inverse problem by using the authors’ empirical data from the experiment.
TL;DR: In this article, a numerical scheme for optimization of surface temperature and vapor volume fraction in subcooled flow boiling is developed, which is based on the finite volume method and Euler-Euler approach to numerically simulate the flow field.
TL;DR: Bubble growth behavior and heat transfer characteristics during subcooled flow boiling in segmented finned microchannels have been numerically investigated in this article, where simulations have been performed for a single row of segmented microchannel and predicted results are compared with experimental investigations.
TL;DR: In this article, the effects of liquid subcooling, surface coating, material property, and surface oxidation on transient pool boiling heat transfer were investigated experimentally using the vertical metal rod and quenching method.
TL;DR: A new correlation for predicting heat transfer in plain channels and annuli is presented in this paper, which has been verified with data for 13 diverse fluids (water, refrigerants, chemicals) in single and multi channels as well as annuli over a very wide range of test data.
TL;DR: In this paper, the impacts of roughness and inhibitor concentration on the freezing temperature, subcooling and the heterogeneous nucleation energy at the surface of aluminum, copper and Teflon plates were studied.
TL;DR: In this paper, the phase change effect during the filling process is taken into account by embedding a pair of mass and heat transfer models into the CFD software FLUENT, one of which involves liquid flash driven by pressure difference between the fluid saturated pressure and the tank pressure, and the other one indicates and calculates the evaporation-condensation process driven by temperature difference between fluid and its saturated state.
TL;DR: In this paper, a second-law-based analysis of the vapor-compression refrigeration cycle is presented, which leads to a set of explicit theoretical formulas for the coefficient of performance (COP).
TL;DR: In this article, a thermodynamic analysis is performed to study the operation characteristics of the sub-cooling CO 2 transcritical refrigeration cycle, and the results indicate that a maximum COP is achieved at the corresponding optimum discharge pressure and the optimum subcooling temperature.
TL;DR: In this article, a large aspect ratio microchannel was investigated in a rectangular microchannel 300mm deep and 6mm wide with the combined effects on the flow boiling phenomena characterized by the Boiling number at an inlet temperature of 65°C.