{ "article_id": 1249, "public_id": "c8c47ecc-89e2-499a-a829-d832a85afc50", "internal_identifier": null, "source_identifier": "84:92", "status": "published", "type": "research_article", "title": "Geriye Dönük Adım Akışında Adım Geometrisinin Isı Transferi ve Akış Yapısı Üzerindeki Etkisinin İncelenmesi", "title_secondary": null, "abstract": "Gaz türbini motorları, yakıcılar, ısıtma ve soğutma sistemleri gibi birçok mühendislik uygulamasında geriye dönük adım akışı nedeniyle ayrılma ve yeniden birleşme bölgeleri meydana gelmektedir. Bu bölgelerin kontrolü, ısı ve kütle transferi miktarını artırmak için oldukça önemlidir. Bu çalışmada, akış ayrılması ve yeniden birleşmesinin etkisini incelemek amacıyla dikey olarak konumlandırılmış geriye dönük adım akışı geometrisinde h/4 ve h/2 olmak üzere farklı pah uzunluklu adım köşe yapılarının pahsız (normal) geometriye göre ısı transferi ve akış karakteristikleri sayısal olarak incelenmiştir. Geriye dönük adımın arkasındaki duvarlardan biri sabit sıcaklıkta tutulurken diğerleri adyabatiktir. Çalışmanın sonuçları, üç boyutlu ve zamandan bağımsız olarak korunum denklemlerinin k-ε türbülans modelli, Boussinesq yaklaşımıyla ANSYS-FLUENT bilgisayar programıyla çözülmesiyle elde edilmiştir. Çalışma akışkanı olarak su ve sıvı sodyum kullanılmıştır. Geriye dönük adımın genişleme oranı 1.5’ dir. Sunulan çalışma, literatürde bulunan çalışmanın sayısal sonuçlarıyla karşılaştırılmış olup birbirleriyle uyumlu ve kabul edilebilir oldukları görülmüştür. Sonuçlar, Nu sayısı, akışkan sıcaklık, türbülans kinetik enerji ve basınç değişimleri olarak sunulmuştur. Ayrıca, geriye dönük adım akışı geometrisinde, sıcaklık, hız ve akım çizgisi dağılımları görselleştirilmiştir. Re=5000 için sıvı sodyum akışında pahsız (normal) geometrinin ortalama Nu sayısı değerinin, h/2 pah uzunluklu geriye dönük adım geometrisinden %9 daha fazla olduğu belirlenmiştir.   ", "language": "tr", "english_title": "Investigation of the Effect of Step Geometry on Heat Transfer and Flow Structure at Backward-Facing Step Flow", "english_abstract": "In many engineering applications such as gas turbine engines, burners, heating and cooling systems, separation and reattachment areas occur due to the backward-facing step flow. Control of these areas is very important to increase the amount of heat and mass transfer. In this study, in order to examine the effect of flow separation and reattachment, the heat transfer and flow characteristics of step corner structures with different chamfer lengths as h/4 and h/2 according to without chamfer (normal) geometry have been numerically researched in the vertically positioned backward-facing step flow geometry. One of the walls behind the backward-facing step has been kept at a constant temperature while the others are adiabatic. The results of the study have been obtained by solving conservation equations with three dimensional and steady k-ε turbulence model with Boussinesq approach using ANSYS-FLUENT computer program. Water and liquid sodium have been used as working fluids. Expansion rate of the backward-facing step is 1.5. The work has been performed at different Reynolds numbers as 5000 and 10000. The present study has been compared with the numerical results of the work found in the literature and it has been found that they are compatible and acceptable with each other. The results have been presented as the variations of Nu number, fluid temperature, turbulence kinetic energy and pressure. In addition, temperature, velocity and streamline distributions have been visualized in backward-facing step flow geometry. For Re=5000, the average Nu number value of the step geometry without chamfer (normal) in the liquid sodium flow has been determined to be 9% higher than the backward-facing step geometry with h/2 chamfer length.", "doi": "10.36287/setsci.4.6.092", "doi_url": "https://doi.org/10.36287/setsci.4.6.092", "resource_url": "https://www.set-science.com/a/c8c47ecc-89e2-499a-a829-d832a85afc50", "pdf_url": "https://www.set-science.com/a/c8c47ecc-89e2-499a-a829-d832a85afc50/pdf", "og_image": "https://www.set-science.com/assets/img/og-card-v2.png", "authors": [ { "public_id": "5c225d99-0834-49b0-8ac4-542d50dcc494", "given": "Koray", "family": "Karabulut", "full": "Koray Karabulut", "literal": null, "orcid": null, "orcid_url": null, "email": "kkarabulut@cumhuriyet.edu.tr", "corresponding": true, "sequence": "first", "affiliations": [ { "name": "Sivas Cumhuriyet University", "department": null, "country": null, "country_code": null, "ror": null, "ror_url": null } ] }, { "public_id": "61eaf584-68c4-463a-87e4-d96e9d40bd51", "given": "Doğan Engin", "family": "Alnak", "full": "Doğan Engin Alnak", "literal": null, "orcid": null, "orcid_url": null, "email": "kkarabulut@cumhuriyet.edu.tr", "corresponding": false, "sequence": "additional", "affiliations": [ { "name": "Sivas Cumhuriyet University", "department": null, "country": null, "country_code": null, "ror": null, "ror_url": null } ] } ], "keywords": [], "translations": [ { "language": "en", "title": "Investigation of the Effect of Step Geometry on Heat Transfer and Flow Structure at Backward-Facing Step Flow", "abstract": "In many engineering applications such as gas turbine engines, burners, heating and cooling systems, separation and reattachment areas occur due to the backward-facing step flow. Control of these areas is very important to increase the amount of heat and mass transfer. In this study, in order to examine the effect of flow separation and reattachment, the heat transfer and flow characteristics of step corner structures with different chamfer lengths as h/4 and h/2 according to without chamfer (normal) geometry have been numerically researched in the vertically positioned backward-facing step flow geometry. One of the walls behind the backward-facing step has been kept at a constant temperature while the others are adiabatic. The results of the study have been obtained by solving conservation equations with three dimensional and steady k-ε turbulence model with Boussinesq approach using ANSYS-FLUENT computer program. Water and liquid sodium have been used as working fluids. Expansion rate of the backward-facing step is 1.5. The work has been performed at different Reynolds numbers as 5000 and 10000. The present study has been compared with the numerical results of the work found in the literature and it has been found that they are compatible and acceptable with each other. The results have been presented as the variations of Nu number, fluid temperature, turbulence kinetic energy and pressure. In addition, temperature, velocity and streamline distributions have been visualized in backward-facing step flow geometry. For Re=5000, the average Nu number value of the step geometry without chamfer (normal) in the liquid sodium flow has been determined to be 9% higher than the backward-facing step geometry with h/2 chamfer length.", "keywords": [ "Ayrılmış akış, geriye dönük adım akışı, ısı transferi, sıvı sodyum, soğutma" ] } ], "subjects": [], "subject_names": [], "published_date": "2019-12-22", "published_year": "2019", "received_date": null, "accepted_date": null, "volume": "9", "issue": null, "page_first": "373", "page_last": "383", "article_number": null, "conference": { "short_name": "ISAS WINTER-2019 (ENS)", "full_title": "4th International Symposium on Innovative Approaches in Engineering and Natural Sciences", "name": "4th International Symposium on Innovative Approaches in Engineering and Natural Sciences", "acronym": "ISAS WINTER-2019 (ENS)", "location": "Samsun, Türkiye", "start_date": "2019-11-22", "end_date": null, "public_id": "ede2435c-3820-4bef-84a9-59e7d8de9d60" }, "proceedings": { "title": "4th International Symposium on Innovative Approaches in Engineering and Natural Sciences", "series_title": "SETSCI Conference Proceedings", "publisher": "SET Technology", "isbn": "978-605-81988-8-3", "eisbn": null, "issn": null, "eissn": "2687-5527", "doi": null, "doi_prefix": "10.36287", "slug": "setsci-volume-9-2019-legacy-84", "public_id": "5d3c128d-5090-429f-8398-4e32c57e5584", "url": "https://www.set-science.com/p/setsci-volume-9-2019-legacy-84" }, "license": { "name": "CC BY 4.0", "url": "https://creativecommons.org/licenses/by/4.0/", "code": "CC-BY-4.0", "open_access": true }, "copyright": { "holder": "SET Technology", "year": "2019" }, "funding_statement": null, "funders": [], "references": [ { "order": 1, "raw": "X. 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