Numerical study of flow and heat transfer during a high-speed micro-drop impact on thin liquid films

Singh, Swati; Saha, A.

doi:10.1016/j.ijheatfluidflow.2021.108808

Cited by 15 publications

(3 citation statements)

References 50 publications

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“…One part involves the qualitative analysis of droplet morphologies captured through high-speed photography. − The observed patterns encompass splashing, jet sheet, crown, vortex, bubble entrapment, and droplet rebound. The second part entails the quantitative analysis of morphological features and heat transfer characteristics using dimensionless numbers such as the Weber number ( We ), Reynolds number ( Re ), Ohnesorge number ( Oh ), and dimensionless film thickness. − Several general rules have been obtained: in terms of dynamics, most studies found that an increase in droplet impact velocity leads to increases in the height and radius of the crown, and within a specific threshold, a rise in film thickness leads to an elevated crown height, but surpassing the threshold causes the opposite effect, with a higher film thickness leading to a decrease in crown radius. Moreover, the Reynolds number has no significant influence on the changes in crown diameter and height.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer and Dynamic Characteristics in Double Droplets’ Impact on Radially Flowing Liquid Film

Shan,

Hu,

Zheng

et al. 2024

Ind. Eng. Chem. Res.

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The process of droplet simultaneous impact and successive impact on the radial flow liquid film is investigated by three-dimensional numerical simulations. The effects of droplet horizontal spacing, vertical spacing, impact velocity, and jet flow rate on the interface evolution characteristics, temperature distribution, and convective heat transfer coefficient distribution are analyzed in detail. The results show that for the simultaneous impact of double droplets on the radial film, a clear middle crown wall is observed in the impact crater. Within a certain range, increases in the jet flow rate and droplet horizontal spacing enhance the cooling effect of the film and expand the area with a high heat transfer coefficient. Despite the fact that the heat transfer coefficient decreases slightly with the increase of impact velocity, the effect brought by impact velocity is not significant. In successive impacts, distinct primary and secondary crowns are produced. For heat transfer characteristics, increasing the jet flow rate increases the heat transfer area and the maximum heat transfer coefficient, but the droplet vertical spacing shows the opposite effects. With regard to the impact velocity, it still demonstrates no remarkable effect on the heat transfer coefficient. The present study provides a fundamental understanding of spray cooling involving multiple droplets' impact on liquid film.

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Section: Introductionmentioning

confidence: 99%

Heat Transfer and Dynamic Characteristics in Double Droplets’ Impact on Radially Flowing Liquid Film

Shan,

Hu,

Zheng

et al. 2024

Ind. Eng. Chem. Res.

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“…Nickel is an important material in many industries, including aerospace, electronics, and automotive, and its thermal properties have been extensively studied. In recent years, the finite element method has gained increasing attention as a promising approach for determining thermal diffusivity in materials [2,3]. This method involves solving the heat diffusion equation using numerical simulations, which can provide accurate and efficient results.…”

Section: Introductionmentioning

confidence: 99%

The Possibility of Using the Finite Element Method for Determining Thermal Diffusivity on the Example of Nickel Using the Classic and The Modified Pulse Method

Szczepaniak,

Terpiłowski,

Woroniak

2023

Adv. Sci. Technol. Res. J.

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The main purpose of the work was to present the possibility of using the finite element method implemented in the COMSOL 3.5a software in the heat transfer symmetry 2D module to determine thermal diffusivity by using the classic and modified pulse methods. The method of determining the thermal diffusivity by means of measuring and recording the course of the temperature difference between the extreme surfaces of the tested sample and changes in the temperature increase on the back surface after a laser shot at its front surface, assuming that the sample is adiabatic for a representative experimental course at a given temperature, was discussed. This paper presents the basic metrological conditions for the implementation of the modified pulse method for testing the temperature characteristics of thermal diffusivity on the example of nickel. The heat pulse generated by using the laser method at the extreme surface of the sample for a thermostatic temperature of 341.8 °C was simulated. Using the inverse problem in both the classic and modified methods, the thermal diffusivity of the material in question was determined and these results were compared with the experimentally obtained values. The values of thermal diffusivity differ from those obtained experimentally by 3.3% for the classic method and approximately 2.5% for the modified method. A preliminary analysis of the influence of the number of nodal points on the numerical results obtained was also carried out and the results for the number of nodes between 64 and 17,000 change by only 1.1%. The paper presents a combination of experimental and numerical studies which is useful in science and simplifies the process of time-consuming experimental studies.

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“…The use of numerical calculations by means of commercial software is increasingly popular, especially in mechanical engineering [ 51 , 52 ]. Comsol Multiphysics software is very frequently used for calculations in the area of heat transfer, as well as for the multi-physics simulation platform [ 53 , 54 ].…”

Section: Introductionmentioning

confidence: 99%

Effect of Surface Topology on the Apparent Thermal Diffusivity of Thin Samples at LFA Measurements

Szczepaniak

2022

Materials

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This paper deals with the problem of the influence of surface topography on the results of thermal diffusivity measurements when determined using the instantaneous surface heat source method, also called the pulse method. The analysis was based on numerical tests carried out using Comsol Multiphysics software. The results of experimental investigations on the actual material structure using an electron microscope, an optical microscope and a profilometer were used to develop a numerical model. The influence of the non-uniformity of the surface of the tested sample on the determined values of half-time of the thermal response of the sample’s rough surface to the impulse forcing on the opposing flat surface was determined by developing the data for simulated measurements. The effect of the position of the response data reading area on the obtained simulation results was also analyzed. The obtained results can be used to improve the accuracy of experimental heat transfer studies performed on thin-film engineering structures depending on the uniformity and parallelism of the material applied to engineering structures. The difference in half-life determination error results for various analyzed models can be as high as 16.7%, depending on the surface from which the responses of the heating impulse are read. With an equivalent model in which 10% of the material volume corresponds to the rough part as a single inclusion, hemisphere, the error in determining thermal diffusivity was equal to 3.8%. An increase in the number of inclusions with smaller weight reduces an error in the determination of thermal diffusivity, as presented in the paper.

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Numerical study of flow and heat transfer during a high-speed micro-drop impact on thin liquid films

Cited by 15 publications

References 50 publications

Heat Transfer and Dynamic Characteristics in Double Droplets’ Impact on Radially Flowing Liquid Film

Heat Transfer and Dynamic Characteristics in Double Droplets’ Impact on Radially Flowing Liquid Film

The Possibility of Using the Finite Element Method for Determining Thermal Diffusivity on the Example of Nickel Using the Classic and The Modified Pulse Method

Effect of Surface Topology on the Apparent Thermal Diffusivity of Thin Samples at LFA Measurements

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