Influence of Narrow Rectangular Channel (AR=1:4) on Heat Transfer and Friction for V- and W-Shaped Ribs in Turbine Blade Applications
Effective cooling of blades with a nominal pressure drop is essential for performance augmentation and thermal management of gas turbines. Hence, present work is aimed at determining the heat transfer enhancement and friction for W- and V-shaped ribs inside a rectangular cooling channel having hydra...
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| Format: | Article |
| Language: | English |
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Wiley
2021-01-01
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| Series: | International Journal of Photoenergy |
| Online Access: | http://dx.doi.org/10.1155/2021/5581081 |
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| author | Karthik Krishnaswamy Suresh Sivan Hafiz Muhammad Ali |
| author_facet | Karthik Krishnaswamy Suresh Sivan Hafiz Muhammad Ali |
| author_sort | Karthik Krishnaswamy |
| collection | DOAJ |
| description | Effective cooling of blades with a nominal pressure drop is essential for performance augmentation and thermal management of gas turbines. Hence, present work is aimed at determining the heat transfer enhancement and friction for W- and V-shaped ribs inside a rectangular cooling channel having hydraulic diameter (Dh) of 0.048 m and aspect ratio (AR) 1 : 4. Ribs are fixed facing downstream with angle of attack (α) 45° on opposite walls. Pitch (P) between two successive ribs is 25 mm for both cases. Continuous V- and W-shaped ribs with height to channel hydraulic diameter ratio (e/Dh) 0.052 and 0.0416 and pitch to height ratio (P/e) 10 and 12.5, respectively, have been examined for Reynolds number (Re) range 20000-80000. Heat transfer augmentation achieved at Re 80000 is 1.94 and 1.8 times higher than Re 20000 for V- and W-shaped ribs, respectively. Streamwise and spanwise variations in local Nusselt number ratio are highest for V-shaped ribs, which are estimated to be 31% and 12%. For W-shaped ribs, variations are 17.5% and 3.5%. Nusselt number (Nu) is highest along span length 0.5w for V-shaped ribs due to dominance of apex induced secondary flow. For W-shaped ribs, Nusselt number along the span lengths is found to be nearly same view uniformity in secondary flow. Maximum enhancement (Nu/Nuo) estimated for both the rib shapes is 3.9 at Re 20000. Due to increased rib height, friction losses for V-shaped ribs are higher than W-shaped ribs. Maximum friction loss increment is estimated to be 85% for V-shaped ribs and 42% for W-shaped ribs between Re 20000 and 40000. For both rib shapes, impact of ribs is found to be greatest at Re 40000. Thermohydraulic performance (THP) for W-shaped ribs is superior to V-shaped ribs. Best THP achieved for W- and V-shaped ribs are 3.7 and 3.4 at Re 20000. |
| format | Article |
| id | doaj-art-4fa8dd03ea5746878e0c3db1a02fd6ca |
| institution | OA Journals |
| issn | 1110-662X 1687-529X |
| language | English |
| publishDate | 2021-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | International Journal of Photoenergy |
| spelling | doaj-art-4fa8dd03ea5746878e0c3db1a02fd6ca2025-08-20T02:05:37ZengWileyInternational Journal of Photoenergy1110-662X1687-529X2021-01-01202110.1155/2021/55810815581081Influence of Narrow Rectangular Channel (AR=1:4) on Heat Transfer and Friction for V- and W-Shaped Ribs in Turbine Blade ApplicationsKarthik Krishnaswamy0Suresh Sivan1Hafiz Muhammad Ali2Mechanical Engineering, National Institute of Technology, Tiruchirappalli 620015, IndiaMechanical Engineering, National Institute of Technology, Tiruchirappalli 620015, IndiaMechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi ArabiaEffective cooling of blades with a nominal pressure drop is essential for performance augmentation and thermal management of gas turbines. Hence, present work is aimed at determining the heat transfer enhancement and friction for W- and V-shaped ribs inside a rectangular cooling channel having hydraulic diameter (Dh) of 0.048 m and aspect ratio (AR) 1 : 4. Ribs are fixed facing downstream with angle of attack (α) 45° on opposite walls. Pitch (P) between two successive ribs is 25 mm for both cases. Continuous V- and W-shaped ribs with height to channel hydraulic diameter ratio (e/Dh) 0.052 and 0.0416 and pitch to height ratio (P/e) 10 and 12.5, respectively, have been examined for Reynolds number (Re) range 20000-80000. Heat transfer augmentation achieved at Re 80000 is 1.94 and 1.8 times higher than Re 20000 for V- and W-shaped ribs, respectively. Streamwise and spanwise variations in local Nusselt number ratio are highest for V-shaped ribs, which are estimated to be 31% and 12%. For W-shaped ribs, variations are 17.5% and 3.5%. Nusselt number (Nu) is highest along span length 0.5w for V-shaped ribs due to dominance of apex induced secondary flow. For W-shaped ribs, Nusselt number along the span lengths is found to be nearly same view uniformity in secondary flow. Maximum enhancement (Nu/Nuo) estimated for both the rib shapes is 3.9 at Re 20000. Due to increased rib height, friction losses for V-shaped ribs are higher than W-shaped ribs. Maximum friction loss increment is estimated to be 85% for V-shaped ribs and 42% for W-shaped ribs between Re 20000 and 40000. For both rib shapes, impact of ribs is found to be greatest at Re 40000. Thermohydraulic performance (THP) for W-shaped ribs is superior to V-shaped ribs. Best THP achieved for W- and V-shaped ribs are 3.7 and 3.4 at Re 20000.http://dx.doi.org/10.1155/2021/5581081 |
| spellingShingle | Karthik Krishnaswamy Suresh Sivan Hafiz Muhammad Ali Influence of Narrow Rectangular Channel (AR=1:4) on Heat Transfer and Friction for V- and W-Shaped Ribs in Turbine Blade Applications International Journal of Photoenergy |
| title | Influence of Narrow Rectangular Channel (AR=1:4) on Heat Transfer and Friction for V- and W-Shaped Ribs in Turbine Blade Applications |
| title_full | Influence of Narrow Rectangular Channel (AR=1:4) on Heat Transfer and Friction for V- and W-Shaped Ribs in Turbine Blade Applications |
| title_fullStr | Influence of Narrow Rectangular Channel (AR=1:4) on Heat Transfer and Friction for V- and W-Shaped Ribs in Turbine Blade Applications |
| title_full_unstemmed | Influence of Narrow Rectangular Channel (AR=1:4) on Heat Transfer and Friction for V- and W-Shaped Ribs in Turbine Blade Applications |
| title_short | Influence of Narrow Rectangular Channel (AR=1:4) on Heat Transfer and Friction for V- and W-Shaped Ribs in Turbine Blade Applications |
| title_sort | influence of narrow rectangular channel ar 1 4 on heat transfer and friction for v and w shaped ribs in turbine blade applications |
| url | http://dx.doi.org/10.1155/2021/5581081 |
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