Film cooling combined with internal impingement cooling is one of the most effective technologies to protect the gas turbine vanes and blades from the hot gas. In this study, conjugate heat transfer CFD study was unde...Film cooling combined with internal impingement cooling is one of the most effective technologies to protect the gas turbine vanes and blades from the hot gas. In this study, conjugate heat transfer CFD study was undertaken for a flat plate with combined film cooling and impingement cooling. An experiment on conjugate heat transfer of a flat plate with combined film and impingement cooling was performed to validate the code. Then the effects of several parameters including Biot number, blowing ratio, film hole shape and impingement hole diameter on the overall cooling effectiveness were numerically studied. The results show that for a specific combined cooling scheme and a given blowing ratio, the coolant potential can be reasonably allocated to the internal and the external cooling to achieve the overall cooling effectiveness. As the blowing ratio increases, the overall cooling effectiveness trends to reach a maximum value. For different film hole geometrical, the maximum values of the overall cooling effectiveness at high blowing ratio approximate to the same value. At a given mass flow rate of coolant, the increase of the impingement hole diameter leads to the reduction of the overall cooling effectiveness.展开更多
This paper presents the results of a numerical study of the effects of swirling flow in coolant jets on film cooling performance.Some combined-hole designs with swirling coolant flow entering the delivery hole are pro...This paper presents the results of a numerical study of the effects of swirling flow in coolant jets on film cooling performance.Some combined-hole designs with swirling coolant flow entering the delivery hole are proposed and analyzed.Adiabatic film cooling effectiveness values for cases with various blowing ratios are compared.Detailed flow structures and underlying mechanisms are discussed.The results show that film cooling effectiveness is improved with jet swirl at high blowing ratios,and that swirl strength has significant influence on film cooling performance.Combined-hole designs can further improve film cooling performance using swirling jets due to mixing of coolant flows and interaction of vortices.The largest improvements of area-averaged film cooling effectiveness for a single-hole swirl case and a combined-hole swirl case over corresponding non-swirling case results are 157%and 173%,respectively.展开更多
春夏干旱是榆中县旱作区胡麻产量的主要限制因素。进一步减少旱地冬春季土壤水分的无效蒸发、提高土壤含水量，为胡麻前期生长创造良好的土壤条件是实现该区胡麻高产稳产的必须步骤。2011—2012年连续两年在地处甘肃省中部半干旱雨养农...春夏干旱是榆中县旱作区胡麻产量的主要限制因素。进一步减少旱地冬春季土壤水分的无效蒸发、提高土壤含水量，为胡麻前期生长创造良好的土壤条件是实现该区胡麻高产稳产的必须步骤。2011—2012年连续两年在地处甘肃省中部半干旱雨养农业区的榆中县石头沟旱作农业示范点进行了组合型微垄全膜覆盖不同覆膜时期对旱地胡麻生长影响的试验。本试验设组合型微垄全膜秋覆盖垄侧栽培、组合型微垄全膜播种前覆盖垄侧栽培和露地穴播三个处理，分别对其土壤水分、经济性状、生育期、产量结果进行分析。结果表明，旱地胡麻组合型微垄全膜秋覆盖垄侧栽培可明显减少冬春季土壤水分的无效蒸发，增加土壤水分含量，0～60 cm 的土壤平均含水量，分别比旱地胡麻微垄全膜播种前覆盖垄侧栽培和旱地胡麻露地穴播栽培高31．9 g·kg -1和45．3 g·kg -1 ；胡麻的经济性状明显改善，株高分别比旱地胡麻微垄全膜播种前覆盖垄侧栽培和旱地胡麻露地穴播栽培高3 ．8 cm 和14．7 cm 、单株蒴果数分别增加8．5个和11．5个 、蒴果粒数分别增加0．6个和1．65个 、千粒重分别提高0．05 g 和0．31 g 。旱地胡麻组合型微垄全膜秋季覆盖垄侧栽培比胡麻露地栽培增产1471．2 kg·hm -2，增幅129．54％，比旱地胡麻微垄全膜播种前覆盖垄侧栽培增产378．22 kg·hm -2，增幅17．41％，增产效果十分明显。展开更多
基金financial support from the National Natural Science Foundation of China under Grant No.51776201the National Science Foundation of Tianjin under Grant No.18JCQNJC07200。
文摘Film cooling combined with internal impingement cooling is one of the most effective technologies to protect the gas turbine vanes and blades from the hot gas. In this study, conjugate heat transfer CFD study was undertaken for a flat plate with combined film cooling and impingement cooling. An experiment on conjugate heat transfer of a flat plate with combined film and impingement cooling was performed to validate the code. Then the effects of several parameters including Biot number, blowing ratio, film hole shape and impingement hole diameter on the overall cooling effectiveness were numerically studied. The results show that for a specific combined cooling scheme and a given blowing ratio, the coolant potential can be reasonably allocated to the internal and the external cooling to achieve the overall cooling effectiveness. As the blowing ratio increases, the overall cooling effectiveness trends to reach a maximum value. For different film hole geometrical, the maximum values of the overall cooling effectiveness at high blowing ratio approximate to the same value. At a given mass flow rate of coolant, the increase of the impingement hole diameter leads to the reduction of the overall cooling effectiveness.
基金supported by Guangdong Basic and Applied Basic Research Foundation,China(No.2019A1515111146)the Fundamental Research Funds for the Central Universities,China(No.3102020HHZY030005)+2 种基金the Natural Science Basic Research Plan in Shaanxi Province of China(No.2021JQ-104)the National Natural Science Foundation of China(No.51676163)the National 111 Project,China(No.B18041)。
文摘This paper presents the results of a numerical study of the effects of swirling flow in coolant jets on film cooling performance.Some combined-hole designs with swirling coolant flow entering the delivery hole are proposed and analyzed.Adiabatic film cooling effectiveness values for cases with various blowing ratios are compared.Detailed flow structures and underlying mechanisms are discussed.The results show that film cooling effectiveness is improved with jet swirl at high blowing ratios,and that swirl strength has significant influence on film cooling performance.Combined-hole designs can further improve film cooling performance using swirling jets due to mixing of coolant flows and interaction of vortices.The largest improvements of area-averaged film cooling effectiveness for a single-hole swirl case and a combined-hole swirl case over corresponding non-swirling case results are 157%and 173%,respectively.
文摘春夏干旱是榆中县旱作区胡麻产量的主要限制因素。进一步减少旱地冬春季土壤水分的无效蒸发、提高土壤含水量，为胡麻前期生长创造良好的土壤条件是实现该区胡麻高产稳产的必须步骤。2011—2012年连续两年在地处甘肃省中部半干旱雨养农业区的榆中县石头沟旱作农业示范点进行了组合型微垄全膜覆盖不同覆膜时期对旱地胡麻生长影响的试验。本试验设组合型微垄全膜秋覆盖垄侧栽培、组合型微垄全膜播种前覆盖垄侧栽培和露地穴播三个处理，分别对其土壤水分、经济性状、生育期、产量结果进行分析。结果表明，旱地胡麻组合型微垄全膜秋覆盖垄侧栽培可明显减少冬春季土壤水分的无效蒸发，增加土壤水分含量，0～60 cm 的土壤平均含水量，分别比旱地胡麻微垄全膜播种前覆盖垄侧栽培和旱地胡麻露地穴播栽培高31．9 g·kg -1和45．3 g·kg -1 ；胡麻的经济性状明显改善，株高分别比旱地胡麻微垄全膜播种前覆盖垄侧栽培和旱地胡麻露地穴播栽培高3 ．8 cm 和14．7 cm 、单株蒴果数分别增加8．5个和11．5个 、蒴果粒数分别增加0．6个和1．65个 、千粒重分别提高0．05 g 和0．31 g 。旱地胡麻组合型微垄全膜秋季覆盖垄侧栽培比胡麻露地栽培增产1471．2 kg·hm -2，增幅129．54％，比旱地胡麻微垄全膜播种前覆盖垄侧栽培增产378．22 kg·hm -2，增幅17．41％，增产效果十分明显。
