Determination of porous constructions heat transfer coefficient

Pavlenko, Аnatoliy; Cheilytko, Andrii; Il'in, S.I.; Belokon, Yuriy

doi:10.1016/j.prostr.2021.12.075

Cited by 3 publications

(2 citation statements)

References 10 publications

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“…Analyzing dependence 1 the main difficulties that must be overcome for the practical application of the proposed mathematical model is the correct determination of the three physical quantities included in the equation -the coefficient taking into account local heat loss, convective heat transfer coefficient and radiative heat transfer coefficient. As is known in engineering practice [2][3][4], the heat transfer coefficient is determined by criterion equations, which must include the Nusselt criterion (Nu) and includes the coefficients of convective and radiative heat transfer (α k +α r ).…”

Section: Methodsmentioning

confidence: 99%

Experimental determination of the heat exchange coefficient of industrial steam pipelines

et al. 2022

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The article discusses and analyses the factors related to the use of a thermal imaging camera to determine heat loss in industrial steam pipelines at factories from chemical and metallurgical industry, by measuring their surface temperature. The generally accepted enthalpy method for determination of the loss has serious drawback it gives accurate results, but in averaged units in which it is impossible to take account of the contribution of the different parts and components of the pipeline in the total heat loss. The unavailability of information on where, how and in what way along the route this loss is formed does not allow prompt and specific measures to be taken for its reduction. An attempt has been made to structure empirically a reliable analytic dependence for determination of the heat exchange coefficient, bringing together the various factors influencing the heat exchange. By the method of the least squares the free coefficient and the exponent have been determined of criterion equation satisfying initial and boundary conditions of the experiment. Based on the obtained results for determining the heat losses by measuring the surface temperature of steam pipelines with a thermal imaging system, a reliable and acceptable method is proposed, which has a place in engineering practice. For this purpose, an industrial experiment has been carried out at three actually operating steam pipelines of different diameters and steam parameters. A criterion equation has been derived that can be used as a mathematical model for software products with a practical orientation for regular assessment of heat losses of steam pipelines. Values of heat losses determined through energy balance of heat carrier and heat flux from the outer surface of the steam pipelines have been compared. Results for the heat exchange coefficient, obtained through a balance have been compared with the analytically determined values based on current standards. A new method has been developed for express evaluations of the current heat losses of the steam pipeline in real time, as the sum of the losses through its individual components gives as average values 9÷12 % increased results for the losses compared to the enthalpy method. Its great advantage is that it can be used selectively to determine the losses through individual sections of the steam pipeline.

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Section: Methodsmentioning

confidence: 99%

Experimental determination of the heat exchange coefficient of industrial steam pipelines

et al. 2022

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“…The porous structures formed through etching offer various advantages by efficiently allowing substances, whether large or small, to pass through [6][7][8][9]. This property plays a crucial role in diverse applications, such as controlling gases or liquids passing through structures of specific sizes by creating fine, porous structures.…”

Section: Introductionmentioning

confidence: 99%

Performance Improvement of an STS304-Based Dispensing Needle via Electrochemical Etching

Kwon,

Jeon,

Lee

et al. 2023

Micromachines

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In this study, we explored the formation of micro-/nanosized porous structures on the surface of a needle composed of STS304 and examined the effect of conventional needles and needles capable of liquid ejection. Aqua regia, composed of HCl and HNO3, was electrochemically etched to form appropriately sized micro-/nanoporous structures. We observed that when dispensing liquids with low surface tension, they do not immediately fall downward but instead spread over the exterior surface of the needle before falling. We found that the extent of spreading on the surface is influenced by an etched porous structure. Furthermore, to analyze the effect of surface tension differences, we dispensed liquids with varying surface tensions using etched needles. Through the analysis, it was confirmed that, despite the low surface tension, the ejected droplet volume and speed could be stably maintained on the etched needle. This indicates that the spreading phenomenon of the liquid on the needle surface just before ejection can be controlled by the micro/nanoporous structure. We anticipate that these characteristics of etched needles could be utilized in industries where precision dispensing of low-surface-tension liquids is essential.

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Mechanical property investigation of welded joints in 10HFTBch steel for the automobile wheel production

Sheyko

Tsyganov

Hrechanyi

et al. 2023

Materials Letters: X

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Determination of porous constructions heat transfer coefficient

Cited by 3 publications

References 10 publications

Experimental determination of the heat exchange coefficient of industrial steam pipelines

Experimental determination of the heat exchange coefficient of industrial steam pipelines

Performance Improvement of an STS304-Based Dispensing Needle via Electrochemical Etching

Mechanical property investigation of welded joints in 10HFTBch steel for the automobile wheel production

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