Wyniki wyszukiwania - Biblioteka Nauki

Nowa wersja platformy, zawierająca wyłącznie zasoby pełnotekstowe, jest już dostępna.
Przejdź na https://bibliotekanauki.pl

Ograniczanie wyników

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Augmentation of Pool Boiling Heat Transfer Using the Laser Treatment Technology

100%

Orman Ł. J. , Honus S. , Radek N. , Kargul M.

Rocznik Ochrona Środowiska

2024

tom Tom 26

160--167

The paper discusses applying the laser technique to modify the copper heater surface. The interaction of the laser beam with the base material leads to its melting, and various shapes can be obtained during the process. The study is focused on the boiling heat transfer analyses of the specimen in the form of a disc with longitudinal microfins of a height of 0.5 mm. The optical microscope was used to determine the morphology of the surface. The laser beam generated significant roughness, which benefitted the overall thermal performance. Considerable heat transfer augmentation was recorded for the laser–made surface in relation to the untreated sample, which served as a reference. The heat flux was several times higher, while the laser–treated sample's boiling curves were shifted to the area of smaller temperature differences. Two boiling models proved unsuccessful in predicting the heat exchange process occurring during pool boiling of distilled water and ethyl alcohol. According to the Smirnov, Xin and Chao models, the average differences between the experimental data and calculation results were ca. 93 kW/m2 and 116 kW/m2 for water, 78 kW/m2 and 68 kW/m2 for ethanol. boiling, heat exchanger, laser beam

Thermal comfort testing in the smart sustainable building

75%

Krawczyk N. , Dębska L. , Honus S. , Zegarek M. , Kiniorski M. , Orman Ł. J.

tom Vol. 7, nr 2

37--45

Today, more and more buildings are being built based on the idea of sustainable development. This mainly concerns the creation of such microclimate conditions in the rooms that a person feels comfortable inside. Therefore, the article presents tests of thermal comfort for three teaching rooms in an intelligent building. The research was carried out using two methods, a microclimate meter measurements and questionnaires. The survey provided research results on thermal sensation vote, thermal preference vote and humidity assessment. Moreover, the results of Predicted Percentage of Dissatisfied and Predicted Mean Vote were presented in the paper. Students between the age of 21 and 25 and one female in her 30s participated in the survey. Through the results of the questionnaires and the microclimate meter, significant differences were shown between the Fanger model and the questionnaires in terms of PMV and PPD.

Formation of coatings with technologies using concentrated energy stream

63%

Radek N. , Kalinowski A. , Pietraszek J. , Orman Ł. J. , Szczepaniak M. , Januszko A. , Kamiński J. , Bronček J. , Paraska O.

2022

tom Vol. 28, Iss. 2

117--122

A number of modern surface processing methods use an energy flux. The examples include electro-spark deposition (ESD) and laser beam processing (LBP). The work concerns the study of Cu-Mo coatings deposited on C45 carbon steel, which were then eroded with a laser beam. The analysis included the analysis of the microstructure, measurements of macrogeometry and microhardness, corrosion resistance tests of selected areas after laser treatment. The coatings were applied with ELFA-541 and subjected to Nd:YAG laser treatment with variable laser parameters. The problem presented in the work can be used to extend the knowledge of the areas of application of ESD coatings, especially in sliding friction pairs.