Jet Impingement Heat Transfer Characteristics with Variable Extended Jet Holes under Strong Crossflow Conditions
In this paper, detailed flow patterns and heat transfer characteristics of a jet impingement system with extended jet holes are experimentally and numerically studied. The jet holes in the jet plate present an inline array of 16 × 5 rows in the streamwise (i.e., the crossflow direction) and spanwise...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-01-01
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| Series: | Aerospace |
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| Online Access: | https://www.mdpi.com/2226-4310/9/1/44 |
| _version_ | 1797496908592185344 |
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| author | Xing Yang Hang Wu Zhenping Feng |
| author_facet | Xing Yang Hang Wu Zhenping Feng |
| author_sort | Xing Yang |
| collection | DOAJ |
| description | In this paper, detailed flow patterns and heat transfer characteristics of a jet impingement system with extended jet holes are experimentally and numerically studied. The jet holes in the jet plate present an inline array of 16 × 5 rows in the streamwise (i.e., the crossflow direction) and spanwise directions, where the streamwise and spanwise distances between adjacent holes, which are normalized by the jet hole diameter (<i>x</i><sub>n</sub>/<i>d</i> and <i>y</i><sub>n</sub>/<i>d</i>), are 8 and 5, respectively. The jets impinge onto a smooth target plate with a normalized distance (<i>z</i><sub>n</sub>/<i>d</i>) of 3.5 apart from the jet plate. The jet holes are extended by inserting stainless tubes throughout the jet holes and the extended lengths are varied in a range of 1.0<i>d</i>–2.5<i>d</i>, depending on the jet position in the streamwise direction. The experimental data is obtained by using the transient thermochromic liquid crystal (TLC) technique for wide operating jet Reynolds numbers of (1.0 × 10<sup>4</sup>)–(3.0 × 10<sup>4</sup>). The numerical simulations are well-validated using the experimental data and provide further insight into the flow physics within the jet impingement system. Comparisons with a traditional baseline jet impingement scheme show that the extended jet holes generate much higher local heat transfer levels and provide more uniform heat transfer distributions over the target plate, resulting in the highest improvement of approximately 36% in the Nusselt number. Although the extended jet hole configuration requires a higher pumping power to drive the flow through the impingement system, the gain of heat transfer prevails over the penalty of flow losses. At the same pumping power consumption, the extended jet hole design also has more than 10% higher heat transfer than the baseline scheme. |
| first_indexed | 2024-03-10T03:10:04Z |
| format | Article |
| id | doaj.art-003881d6d0374f878976810ee358c714 |
| institution | Directory Open Access Journal |
| issn | 2226-4310 |
| language | English |
| last_indexed | 2024-03-10T03:10:04Z |
| publishDate | 2022-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Aerospace |
| spelling | doaj.art-003881d6d0374f878976810ee358c7142023-11-23T12:34:34ZengMDPI AGAerospace2226-43102022-01-01914410.3390/aerospace9010044Jet Impingement Heat Transfer Characteristics with Variable Extended Jet Holes under Strong Crossflow ConditionsXing Yang0Hang Wu1Zhenping Feng2Shanxi Engineering Laboratory of Turbomachinery and Power Equipment, Institute of Turbomachinery, Xi’an Jiaotong University, Xi’an 710049, ChinaShanxi Engineering Laboratory of Turbomachinery and Power Equipment, Institute of Turbomachinery, Xi’an Jiaotong University, Xi’an 710049, ChinaShanxi Engineering Laboratory of Turbomachinery and Power Equipment, Institute of Turbomachinery, Xi’an Jiaotong University, Xi’an 710049, ChinaIn this paper, detailed flow patterns and heat transfer characteristics of a jet impingement system with extended jet holes are experimentally and numerically studied. The jet holes in the jet plate present an inline array of 16 × 5 rows in the streamwise (i.e., the crossflow direction) and spanwise directions, where the streamwise and spanwise distances between adjacent holes, which are normalized by the jet hole diameter (<i>x</i><sub>n</sub>/<i>d</i> and <i>y</i><sub>n</sub>/<i>d</i>), are 8 and 5, respectively. The jets impinge onto a smooth target plate with a normalized distance (<i>z</i><sub>n</sub>/<i>d</i>) of 3.5 apart from the jet plate. The jet holes are extended by inserting stainless tubes throughout the jet holes and the extended lengths are varied in a range of 1.0<i>d</i>–2.5<i>d</i>, depending on the jet position in the streamwise direction. The experimental data is obtained by using the transient thermochromic liquid crystal (TLC) technique for wide operating jet Reynolds numbers of (1.0 × 10<sup>4</sup>)–(3.0 × 10<sup>4</sup>). The numerical simulations are well-validated using the experimental data and provide further insight into the flow physics within the jet impingement system. Comparisons with a traditional baseline jet impingement scheme show that the extended jet holes generate much higher local heat transfer levels and provide more uniform heat transfer distributions over the target plate, resulting in the highest improvement of approximately 36% in the Nusselt number. Although the extended jet hole configuration requires a higher pumping power to drive the flow through the impingement system, the gain of heat transfer prevails over the penalty of flow losses. At the same pumping power consumption, the extended jet hole design also has more than 10% higher heat transfer than the baseline scheme.https://www.mdpi.com/2226-4310/9/1/44gas turbinejet impingement coolingheat transferextended jet holethermochromic liquid crystal (TLC) |
| spellingShingle | Xing Yang Hang Wu Zhenping Feng Jet Impingement Heat Transfer Characteristics with Variable Extended Jet Holes under Strong Crossflow Conditions Aerospace gas turbine jet impingement cooling heat transfer extended jet hole thermochromic liquid crystal (TLC) |
| title | Jet Impingement Heat Transfer Characteristics with Variable Extended Jet Holes under Strong Crossflow Conditions |
| title_full | Jet Impingement Heat Transfer Characteristics with Variable Extended Jet Holes under Strong Crossflow Conditions |
| title_fullStr | Jet Impingement Heat Transfer Characteristics with Variable Extended Jet Holes under Strong Crossflow Conditions |
| title_full_unstemmed | Jet Impingement Heat Transfer Characteristics with Variable Extended Jet Holes under Strong Crossflow Conditions |
| title_short | Jet Impingement Heat Transfer Characteristics with Variable Extended Jet Holes under Strong Crossflow Conditions |
| title_sort | jet impingement heat transfer characteristics with variable extended jet holes under strong crossflow conditions |
| topic | gas turbine jet impingement cooling heat transfer extended jet hole thermochromic liquid crystal (TLC) |
| url | https://www.mdpi.com/2226-4310/9/1/44 |
| work_keys_str_mv | AT xingyang jetimpingementheattransfercharacteristicswithvariableextendedjetholesunderstrongcrossflowconditions AT hangwu jetimpingementheattransfercharacteristicswithvariableextendedjetholesunderstrongcrossflowconditions AT zhenpingfeng jetimpingementheattransfercharacteristicswithvariableextendedjetholesunderstrongcrossflowconditions |