O. Voznyak, N. Spodyniuk, I. Sukholova, Olena Savchenko, M. Kasynets, Serhii Shostak
This article is dedicated to diagnosis of damage to air distribution in a room with twisted, compact, and flat air jets, and to searching of ways to solving the problem. It was found that in order to avoid damage to the air distribution system in rooms of different purposes and dimensions; it should be air streams of the appropriate types and with the appropriate characteristics. Parameters of a swirled, compact, flat, rectangular air jet when creating comfortable climatic conditions in the rooms of different purposes and dimensions are determined. The relationship between the angle of inclination of the rotating plates (for twisted jets), ratio of sides of the slit (for all rectangular including compact and flat streams) and a long-range of these flows is established.
{"title":"Diagnosis of air distribution in a room","authors":"O. Voznyak, N. Spodyniuk, I. Sukholova, Olena Savchenko, M. Kasynets, Serhii Shostak","doi":"10.1556/606.2024.00962","DOIUrl":"https://doi.org/10.1556/606.2024.00962","url":null,"abstract":"This article is dedicated to diagnosis of damage to air distribution in a room with twisted, compact, and flat air jets, and to searching of ways to solving the problem. It was found that in order to avoid damage to the air distribution system in rooms of different purposes and dimensions; it should be air streams of the appropriate types and with the appropriate characteristics. Parameters of a swirled, compact, flat, rectangular air jet when creating comfortable climatic conditions in the rooms of different purposes and dimensions are determined. The relationship between the angle of inclination of the rotating plates (for twisted jets), ratio of sides of the slit (for all rectangular including compact and flat streams) and a long-range of these flows is established.","PeriodicalId":35003,"journal":{"name":"Pollack Periodica","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139777024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Direct resistance check by applying advanced numerical models is getting increasingly used for the design of steel slender plated structures. This method has to take into account the same uncertainties as traditional analytical design calculations and should ensure the Eurocode-based prescribed safety level. The application of the model factor gives the possibility to account for the model-related uncertainties. The current study focuses on the determination of the model factor for one specific failure mode, the patch loading resistance. Numerical model has been developed and validated based on laboratory test results. To evaluate the model uncertainties, physically possible modeling differences are introduced, and their effects are evaluated on the resistance. The final aim of the study is to determine the model factor for the analyzed girder type and failure mode based on statistical evaluation.
{"title":"Model factor for patch loading resistance of steel plated structures","authors":"E. Bärnkopf, B. Kövesdi","doi":"10.1556/606.2024.00981","DOIUrl":"https://doi.org/10.1556/606.2024.00981","url":null,"abstract":"Direct resistance check by applying advanced numerical models is getting increasingly used for the design of steel slender plated structures. This method has to take into account the same uncertainties as traditional analytical design calculations and should ensure the Eurocode-based prescribed safety level. The application of the model factor gives the possibility to account for the model-related uncertainties. The current study focuses on the determination of the model factor for one specific failure mode, the patch loading resistance. Numerical model has been developed and validated based on laboratory test results. To evaluate the model uncertainties, physically possible modeling differences are introduced, and their effects are evaluated on the resistance. The final aim of the study is to determine the model factor for the analyzed girder type and failure mode based on statistical evaluation.","PeriodicalId":35003,"journal":{"name":"Pollack Periodica","volume":"8 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139777781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
O. Voznyak, N. Spodyniuk, I. Sukholova, Olena Savchenko, M. Kasynets, Serhii Shostak
This article is dedicated to diagnosis of damage to air distribution in a room with twisted, compact, and flat air jets, and to searching of ways to solving the problem. It was found that in order to avoid damage to the air distribution system in rooms of different purposes and dimensions; it should be air streams of the appropriate types and with the appropriate characteristics. Parameters of a swirled, compact, flat, rectangular air jet when creating comfortable climatic conditions in the rooms of different purposes and dimensions are determined. The relationship between the angle of inclination of the rotating plates (for twisted jets), ratio of sides of the slit (for all rectangular including compact and flat streams) and a long-range of these flows is established.
{"title":"Diagnosis of air distribution in a room","authors":"O. Voznyak, N. Spodyniuk, I. Sukholova, Olena Savchenko, M. Kasynets, Serhii Shostak","doi":"10.1556/606.2024.00962","DOIUrl":"https://doi.org/10.1556/606.2024.00962","url":null,"abstract":"This article is dedicated to diagnosis of damage to air distribution in a room with twisted, compact, and flat air jets, and to searching of ways to solving the problem. It was found that in order to avoid damage to the air distribution system in rooms of different purposes and dimensions; it should be air streams of the appropriate types and with the appropriate characteristics. Parameters of a swirled, compact, flat, rectangular air jet when creating comfortable climatic conditions in the rooms of different purposes and dimensions are determined. The relationship between the angle of inclination of the rotating plates (for twisted jets), ratio of sides of the slit (for all rectangular including compact and flat streams) and a long-range of these flows is established.","PeriodicalId":35003,"journal":{"name":"Pollack Periodica","volume":"97 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139836730","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Direct resistance check by applying advanced numerical models is getting increasingly used for the design of steel slender plated structures. This method has to take into account the same uncertainties as traditional analytical design calculations and should ensure the Eurocode-based prescribed safety level. The application of the model factor gives the possibility to account for the model-related uncertainties. The current study focuses on the determination of the model factor for one specific failure mode, the patch loading resistance. Numerical model has been developed and validated based on laboratory test results. To evaluate the model uncertainties, physically possible modeling differences are introduced, and their effects are evaluated on the resistance. The final aim of the study is to determine the model factor for the analyzed girder type and failure mode based on statistical evaluation.
{"title":"Model factor for patch loading resistance of steel plated structures","authors":"E. Bärnkopf, B. Kövesdi","doi":"10.1556/606.2024.00981","DOIUrl":"https://doi.org/10.1556/606.2024.00981","url":null,"abstract":"Direct resistance check by applying advanced numerical models is getting increasingly used for the design of steel slender plated structures. This method has to take into account the same uncertainties as traditional analytical design calculations and should ensure the Eurocode-based prescribed safety level. The application of the model factor gives the possibility to account for the model-related uncertainties. The current study focuses on the determination of the model factor for one specific failure mode, the patch loading resistance. Numerical model has been developed and validated based on laboratory test results. To evaluate the model uncertainties, physically possible modeling differences are introduced, and their effects are evaluated on the resistance. The final aim of the study is to determine the model factor for the analyzed girder type and failure mode based on statistical evaluation.","PeriodicalId":35003,"journal":{"name":"Pollack Periodica","volume":"100 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139837392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study evaluated the thermal performance of side divergence and uniform micro-channel heat sinks by comparing and contrasting them. Heat transfer and fluid flow characteristics in these micro-channel configurations were studied using computational fluid dynamics simulations employing ANSYS Fluent 2017 code for this purpose. Laminar flow through micro-channels with a Reynolds number of 207 was the subject of the investigation. The goal is to determine how side divergence affects heat dissipation efficiency concerning traditional uniform micro-channels. The results showed that the best divergence ratio is 1.5 that achieved the highest performance. The study also revealed that side divergence micro-channel heat sinks can achieve thermal performance up to 14% higher than uniform micro-channel heat sinks.
{"title":"Comparative analysis of microchannel heat sinks for thermal performance enhancement","authors":"Dhay Abd Al Hasan Jawad, S. Ahmed","doi":"10.1556/606.2023.00989","DOIUrl":"https://doi.org/10.1556/606.2023.00989","url":null,"abstract":"This study evaluated the thermal performance of side divergence and uniform micro-channel heat sinks by comparing and contrasting them. Heat transfer and fluid flow characteristics in these micro-channel configurations were studied using computational fluid dynamics simulations employing ANSYS Fluent 2017 code for this purpose. Laminar flow through micro-channels with a Reynolds number of 207 was the subject of the investigation. The goal is to determine how side divergence affects heat dissipation efficiency concerning traditional uniform micro-channels. The results showed that the best divergence ratio is 1.5 that achieved the highest performance. The study also revealed that side divergence micro-channel heat sinks can achieve thermal performance up to 14% higher than uniform micro-channel heat sinks.","PeriodicalId":35003,"journal":{"name":"Pollack Periodica","volume":"64 49","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139778847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Integrating thermal energy storage with thermal conversion systems is necessary to maximize their use. Phase change materials are the best media for storing and releasing thermal energy from various basic material types. Because the phase change materials have a high latent heat of fusion, it is often viable to use these characteristics and include the phase change materials in building envelopes to store thermal energy. The paper provides a thorough categorization of the phase change materials and thermal energy storage systems, in addition to an evaluation of their modeling using computational fluid dynamics. The purpose was to highlight computational fluid dynamics as a useful technique for advancing the engineering of thermal energy storage devices.
{"title":"CFD modeling for phase change materials integrated to building envelope","authors":"Ammar Saliby, Béla Kovács","doi":"10.1556/606.2023.00930","DOIUrl":"https://doi.org/10.1556/606.2023.00930","url":null,"abstract":"Integrating thermal energy storage with thermal conversion systems is necessary to maximize their use. Phase change materials are the best media for storing and releasing thermal energy from various basic material types. Because the phase change materials have a high latent heat of fusion, it is often viable to use these characteristics and include the phase change materials in building envelopes to store thermal energy. The paper provides a thorough categorization of the phase change materials and thermal energy storage systems, in addition to an evaluation of their modeling using computational fluid dynamics. The purpose was to highlight computational fluid dynamics as a useful technique for advancing the engineering of thermal energy storage devices.","PeriodicalId":35003,"journal":{"name":"Pollack Periodica","volume":"527 3","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139836924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Integrating thermal energy storage with thermal conversion systems is necessary to maximize their use. Phase change materials are the best media for storing and releasing thermal energy from various basic material types. Because the phase change materials have a high latent heat of fusion, it is often viable to use these characteristics and include the phase change materials in building envelopes to store thermal energy. The paper provides a thorough categorization of the phase change materials and thermal energy storage systems, in addition to an evaluation of their modeling using computational fluid dynamics. The purpose was to highlight computational fluid dynamics as a useful technique for advancing the engineering of thermal energy storage devices.
{"title":"CFD modeling for phase change materials integrated to building envelope","authors":"Ammar Saliby, Béla Kovács","doi":"10.1556/606.2023.00930","DOIUrl":"https://doi.org/10.1556/606.2023.00930","url":null,"abstract":"Integrating thermal energy storage with thermal conversion systems is necessary to maximize their use. Phase change materials are the best media for storing and releasing thermal energy from various basic material types. Because the phase change materials have a high latent heat of fusion, it is often viable to use these characteristics and include the phase change materials in building envelopes to store thermal energy. The paper provides a thorough categorization of the phase change materials and thermal energy storage systems, in addition to an evaluation of their modeling using computational fluid dynamics. The purpose was to highlight computational fluid dynamics as a useful technique for advancing the engineering of thermal energy storage devices.","PeriodicalId":35003,"journal":{"name":"Pollack Periodica","volume":"26 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139777471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maher F. Al Lebban, Ameer A. Alraie, Q. A. Jabal, Laith Abdul Rasool Alasadi, Rawa Shakir Muwashee, W. H. Mahdi
Progress in building construction requires more durable concrete with higher strength. Polymer and water reducer liquids can improve concrete strength and durability. This research aims to improve the mechanical properties of polymer-modified concrete by using anti-slip sand and silica fume to achieve more durable concrete against sulfate attack and higher mechanical properties. The study shows an increase in compressive strength from 25.7 MPa for reference mix to 45.5 MPa using 15% silica fume and 30% Anti-slip sand; tensile strength increased from 2.72 to 4.4 MPa. Flexural strength also increased, and durability to sulfate attack also increased. The study includes the increment of durability against freezing-thawing cycles for different mixes.
{"title":"The effect of anti-slip aggregate and silica fume on polymer-modified concrete","authors":"Maher F. Al Lebban, Ameer A. Alraie, Q. A. Jabal, Laith Abdul Rasool Alasadi, Rawa Shakir Muwashee, W. H. Mahdi","doi":"10.1556/606.2023.00958","DOIUrl":"https://doi.org/10.1556/606.2023.00958","url":null,"abstract":"Progress in building construction requires more durable concrete with higher strength. Polymer and water reducer liquids can improve concrete strength and durability. This research aims to improve the mechanical properties of polymer-modified concrete by using anti-slip sand and silica fume to achieve more durable concrete against sulfate attack and higher mechanical properties. The study shows an increase in compressive strength from 25.7 MPa for reference mix to 45.5 MPa using 15% silica fume and 30% Anti-slip sand; tensile strength increased from 2.72 to 4.4 MPa. Flexural strength also increased, and durability to sulfate attack also increased. The study includes the increment of durability against freezing-thawing cycles for different mixes.","PeriodicalId":35003,"journal":{"name":"Pollack Periodica","volume":"739 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139838883","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The structural assessment of historical buildings poses a significant challenge for engineers. However, when it comes to historical structures, more commonly used and reliable destructive testing may not always be viable. Instead, non-destructive testing has gained prominence, encompassing techniques like the Schmidt hammer test, georadar, and sonic-based tests.In this paper, the viability of employing sonic testing on historical masonry structures was investigated. This study involves using the measured sonic velocities to identify voids and solid parts within masonry walls. In addition, the purpose is to determine the compressive strength of both mortar and brick constituents and to analyze the effects of moisture and compressive stress on the propagation velocity of waves.
{"title":"Experimental investigation of the sonic velocity in historical masonry walls","authors":"A. Dormany, Z. Orbán","doi":"10.1556/606.2023.00945","DOIUrl":"https://doi.org/10.1556/606.2023.00945","url":null,"abstract":"The structural assessment of historical buildings poses a significant challenge for engineers. However, when it comes to historical structures, more commonly used and reliable destructive testing may not always be viable. Instead, non-destructive testing has gained prominence, encompassing techniques like the Schmidt hammer test, georadar, and sonic-based tests.In this paper, the viability of employing sonic testing on historical masonry structures was investigated. This study involves using the measured sonic velocities to identify voids and solid parts within masonry walls. In addition, the purpose is to determine the compressive strength of both mortar and brick constituents and to analyze the effects of moisture and compressive stress on the propagation velocity of waves.","PeriodicalId":35003,"journal":{"name":"Pollack Periodica","volume":"63 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139780377","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work investigates the effect of two wall roughness types, triangular and circular, on convection and radiation heat transfer in a small space. The ANSYS Fluent is used to do thermal and dynamic modeling; the left wall is warmer than the right one. The upper and lower walls are adiabatic. The Nusselt numbers are compared in all cases and for two Rayleigh values, which change based on the cavity's characteristic length. The results show temperature contours and Nusselt curves. It was observed that the roughness had a strong effect on the air's thermal behavior inside the cavity, where the Nusselt decreased in both roughness cases, especially at small heights. However, the largest decrease is in the triangular case and for angles less than 90°. For 72°, Nusselt is 13.32 and 6% less than smooth and circular cases respectively.
{"title":"Impact of wall roughness elements type and height on heat transfer inside a cavity","authors":"Issa Omle, A. Askar, Endre Kovács","doi":"10.1556/606.2024.00986","DOIUrl":"https://doi.org/10.1556/606.2024.00986","url":null,"abstract":"This work investigates the effect of two wall roughness types, triangular and circular, on convection and radiation heat transfer in a small space. The ANSYS Fluent is used to do thermal and dynamic modeling; the left wall is warmer than the right one. The upper and lower walls are adiabatic. The Nusselt numbers are compared in all cases and for two Rayleigh values, which change based on the cavity's characteristic length. The results show temperature contours and Nusselt curves. It was observed that the roughness had a strong effect on the air's thermal behavior inside the cavity, where the Nusselt decreased in both roughness cases, especially at small heights. However, the largest decrease is in the triangular case and for angles less than 90°. For 72°, Nusselt is 13.32 and 6% less than smooth and circular cases respectively.","PeriodicalId":35003,"journal":{"name":"Pollack Periodica","volume":"358 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139841612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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