Orhan YALÇINKAYA, Mehmet Berkant ÖZEL, Ufuk DURMAZ, Ünal UYSAL
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The study examined how the interaction between pin heights and nozzle lengths influences heat transfer in a channel-confined impinging jet flow. The analysis included evaluating heat transfer performance in different jet regions and assessing pressure loss coefficients for various configurations.</p></div><div><h3>Significant Findings</h3><p>Results indicated that for smooth target surfaces, elongated nozzles increased heat transfer in the first two jet regions but decreased it in the last jet regions due to cross-flow effects. In contrast, conical pinned surfaces showed a significant increase in heat transfer, particularly in the stagnation and last jet regions, with lower <em>G/d</em> and higher <em>H</em><sub><em>c</em></sub><em>/d</em> values. Conical pinned surfaces enhanced overall heat transfer by at least 5 % compared to smooth surfaces, with a maximum Nu number increase of 21.87 %. However, configurations with <em>G/d</em> < 2.0 and <em>H</em><sub><em>c</em></sub><em>/d</em> ≤ 0.67 negatively impacted heat transfer. Pressure loss analysis revealed that using conical pins and extended jets together increased pressure loss, with a maximum drop of 5.67 kPa at <em>Re</em> = 39,000. The Thermal Performance Criterion (TPC) ranged from a minimum of 0.97 at <em>Re</em> = 26,000 (<em>G/d</em> = 1.0, <em>H</em><sub><em>c</em></sub><em>/d</em> = 1.00) to a maximum of 1.18 at <em>Re</em> = 26,000 (<em>G/d</em> = 6.0, <em>H</em><sub><em>c</em></sub><em>/d</em> = 1.33).</p></div>","PeriodicalId":381,"journal":{"name":"Journal of the Taiwan Institute of Chemical Engineers","volume":"164 ","pages":"Article 105709"},"PeriodicalIF":5.5000,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Experimental heat transfer analysis of conical pin configurations in jet impingement cooling with elongated nozzle holes\",\"authors\":\"Orhan YALÇINKAYA, Mehmet Berkant ÖZEL, Ufuk DURMAZ, Ünal UYSAL\",\"doi\":\"10.1016/j.jtice.2024.105709\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><h3>Background</h3><p>This study investigates the impact of jet impingement cooling with varying nozzle lengths on the heat transfer performance of smooth and conical pinned target surfaces under turbulent flow conditions. The study focuses on the Reynolds numbers (<em>Re</em>) of 13,000, 26,000, and 39,000, using the liquid crystal thermography (TLC) method to collect experimental data. The dimensionless conical pin heights (<em>H</em><sub><em>c</em></sub><em>/d</em> = 0.00, 0.67, 1.00, 1.33) and target surface-nozzle distances (<em>G/d</em> = 1.0, 2.0, 3.0, 6.0) were analyzed to understand their effects on heat transfer.</p></div><div><h3>Methods</h3><p>The experimental setup involved measuring Nu numbers and pressure losses in models with elongated nozzles and conical pins. The study examined how the interaction between pin heights and nozzle lengths influences heat transfer in a channel-confined impinging jet flow. The analysis included evaluating heat transfer performance in different jet regions and assessing pressure loss coefficients for various configurations.</p></div><div><h3>Significant Findings</h3><p>Results indicated that for smooth target surfaces, elongated nozzles increased heat transfer in the first two jet regions but decreased it in the last jet regions due to cross-flow effects. In contrast, conical pinned surfaces showed a significant increase in heat transfer, particularly in the stagnation and last jet regions, with lower <em>G/d</em> and higher <em>H</em><sub><em>c</em></sub><em>/d</em> values. Conical pinned surfaces enhanced overall heat transfer by at least 5 % compared to smooth surfaces, with a maximum Nu number increase of 21.87 %. However, configurations with <em>G/d</em> < 2.0 and <em>H</em><sub><em>c</em></sub><em>/d</em> ≤ 0.67 negatively impacted heat transfer. Pressure loss analysis revealed that using conical pins and extended jets together increased pressure loss, with a maximum drop of 5.67 kPa at <em>Re</em> = 39,000. 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Experimental heat transfer analysis of conical pin configurations in jet impingement cooling with elongated nozzle holes
Background
This study investigates the impact of jet impingement cooling with varying nozzle lengths on the heat transfer performance of smooth and conical pinned target surfaces under turbulent flow conditions. The study focuses on the Reynolds numbers (Re) of 13,000, 26,000, and 39,000, using the liquid crystal thermography (TLC) method to collect experimental data. The dimensionless conical pin heights (Hc/d = 0.00, 0.67, 1.00, 1.33) and target surface-nozzle distances (G/d = 1.0, 2.0, 3.0, 6.0) were analyzed to understand their effects on heat transfer.
Methods
The experimental setup involved measuring Nu numbers and pressure losses in models with elongated nozzles and conical pins. The study examined how the interaction between pin heights and nozzle lengths influences heat transfer in a channel-confined impinging jet flow. The analysis included evaluating heat transfer performance in different jet regions and assessing pressure loss coefficients for various configurations.
Significant Findings
Results indicated that for smooth target surfaces, elongated nozzles increased heat transfer in the first two jet regions but decreased it in the last jet regions due to cross-flow effects. In contrast, conical pinned surfaces showed a significant increase in heat transfer, particularly in the stagnation and last jet regions, with lower G/d and higher Hc/d values. Conical pinned surfaces enhanced overall heat transfer by at least 5 % compared to smooth surfaces, with a maximum Nu number increase of 21.87 %. However, configurations with G/d < 2.0 and Hc/d ≤ 0.67 negatively impacted heat transfer. Pressure loss analysis revealed that using conical pins and extended jets together increased pressure loss, with a maximum drop of 5.67 kPa at Re = 39,000. The Thermal Performance Criterion (TPC) ranged from a minimum of 0.97 at Re = 26,000 (G/d = 1.0, Hc/d = 1.00) to a maximum of 1.18 at Re = 26,000 (G/d = 6.0, Hc/d = 1.33).
期刊介绍：
Journal of the Taiwan Institute of Chemical Engineers (formerly known as Journal of the Chinese Institute of Chemical Engineers) publishes original works, from fundamental principles to practical applications, in the broad field of chemical engineering with special focus on three aspects: Chemical and Biomolecular Science and Technology, Energy and Environmental Science and Technology, and Materials Science and Technology. Authors should choose for their manuscript an appropriate aspect section and a few related classifications when submitting to the journal online.
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