Graphene far-infrared drying wheat: Heat transfer and energy behaviors
Graphene far-infrared (g-FIR) drying offers an energy-efficient alternative to conventional grain drying. This study investigates the thermodynamic behavior of wheat in a novel g-FIR drying system integrating radiative-conductive heating and forced convection. Through multifactorial experiments (g-F...
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| Format: | Article |
| Language: | English |
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Elsevier
2025-10-01
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| Series: | Case Studies in Thermal Engineering |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2214157X25011244 |
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| author | Jianchun Yan Qing Zhao Hai Wei Jiyou An Kunjie Chen Huanxiong Xie |
| author_facet | Jianchun Yan Qing Zhao Hai Wei Jiyou An Kunjie Chen Huanxiong Xie |
| author_sort | Jianchun Yan |
| collection | DOAJ |
| description | Graphene far-infrared (g-FIR) drying offers an energy-efficient alternative to conventional grain drying. This study investigates the thermodynamic behavior of wheat in a novel g-FIR drying system integrating radiative-conductive heating and forced convection. Through multifactorial experiments (g-FIR temperature: 50–70 °C; airflow temperature: 30–60 °C; air volume rate: 1.2–3.0 m3/min; grain throughput: 0.0078–0.0128 m3/min), the contributions of radiative and conductive heat transfer were decoupled based on the modelling of heat balance between grain, graphene heater, and airflow. Results revealed that radiative heating accounted for only 20–27 % of total heat absorbed by grains, with conductive transfer dominating due to direct grain-emitter contact. Elevated g-FIR temperatures accelerated drying through enhanced internal moisture diffusivity, while airflow temperature increases primarily amplified surface vapor gradients. A critical air volume rate (2.4 m3/min) optimized moisture removal without excessive grain cooling, while throughput below 0.0103 m3/min caused thermal saturation inefficiencies as wall-proximal grains reached the graphene heater temperature before exiting. The derived equivalent contact conductance model demonstrated moisture- and temperature-difference-dependent thermal transport dynamics. Optimal parameters (60 °C g-FIR, 30 °C airflow, 2.4 m3/min air volume, 0.0103 m3/min throughput) achieved 72.3 % cumulative energy efficiency and 3.31 MJ/kg specific energy consumption. This work establishes a framework for designing energy-efficient hybrid dryers, highlighting the necessity of crop-specific optimization to reconcile thermal input with moisture removal kinetics. |
| format | Article |
| id | doaj-art-93dd2c07849d4c8fb8f5af84b00a3624 |
| institution | Kabale University |
| issn | 2214-157X |
| language | English |
| publishDate | 2025-10-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Case Studies in Thermal Engineering |
| spelling | doaj-art-93dd2c07849d4c8fb8f5af84b00a36242025-08-24T05:12:42ZengElsevierCase Studies in Thermal Engineering2214-157X2025-10-017410686410.1016/j.csite.2025.106864Graphene far-infrared drying wheat: Heat transfer and energy behaviorsJianchun Yan0Qing Zhao1Hai Wei2Jiyou An3Kunjie Chen4Huanxiong Xie5Nanjing Agricultural University, China; Nanjing Institute of Agricultural Mechanization, Ministry of Agriculture and Rural Affairs, ChinaAgriculture College of Yangzhou University, ChinaNanjing Institute of Agricultural Mechanization, Ministry of Agriculture and Rural Affairs, ChinaNanjing Institute of Agricultural Mechanization, Ministry of Agriculture and Rural Affairs, ChinaNanjing Agricultural University, China; Corresponding author.Nanjing Institute of Agricultural Mechanization, Ministry of Agriculture and Rural Affairs, ChinaGraphene far-infrared (g-FIR) drying offers an energy-efficient alternative to conventional grain drying. This study investigates the thermodynamic behavior of wheat in a novel g-FIR drying system integrating radiative-conductive heating and forced convection. Through multifactorial experiments (g-FIR temperature: 50–70 °C; airflow temperature: 30–60 °C; air volume rate: 1.2–3.0 m3/min; grain throughput: 0.0078–0.0128 m3/min), the contributions of radiative and conductive heat transfer were decoupled based on the modelling of heat balance between grain, graphene heater, and airflow. Results revealed that radiative heating accounted for only 20–27 % of total heat absorbed by grains, with conductive transfer dominating due to direct grain-emitter contact. Elevated g-FIR temperatures accelerated drying through enhanced internal moisture diffusivity, while airflow temperature increases primarily amplified surface vapor gradients. A critical air volume rate (2.4 m3/min) optimized moisture removal without excessive grain cooling, while throughput below 0.0103 m3/min caused thermal saturation inefficiencies as wall-proximal grains reached the graphene heater temperature before exiting. The derived equivalent contact conductance model demonstrated moisture- and temperature-difference-dependent thermal transport dynamics. Optimal parameters (60 °C g-FIR, 30 °C airflow, 2.4 m3/min air volume, 0.0103 m3/min throughput) achieved 72.3 % cumulative energy efficiency and 3.31 MJ/kg specific energy consumption. This work establishes a framework for designing energy-efficient hybrid dryers, highlighting the necessity of crop-specific optimization to reconcile thermal input with moisture removal kinetics.http://www.sciencedirect.com/science/article/pii/S2214157X25011244Wheat dryingGraphene heaterFIRThermal contact conductanceSpecific energy consumptionEnergy efficiency |
| spellingShingle | Jianchun Yan Qing Zhao Hai Wei Jiyou An Kunjie Chen Huanxiong Xie Graphene far-infrared drying wheat: Heat transfer and energy behaviors Case Studies in Thermal Engineering Wheat drying Graphene heater FIR Thermal contact conductance Specific energy consumption Energy efficiency |
| title | Graphene far-infrared drying wheat: Heat transfer and energy behaviors |
| title_full | Graphene far-infrared drying wheat: Heat transfer and energy behaviors |
| title_fullStr | Graphene far-infrared drying wheat: Heat transfer and energy behaviors |
| title_full_unstemmed | Graphene far-infrared drying wheat: Heat transfer and energy behaviors |
| title_short | Graphene far-infrared drying wheat: Heat transfer and energy behaviors |
| title_sort | graphene far infrared drying wheat heat transfer and energy behaviors |
| topic | Wheat drying Graphene heater FIR Thermal contact conductance Specific energy consumption Energy efficiency |
| url | http://www.sciencedirect.com/science/article/pii/S2214157X25011244 |
| work_keys_str_mv | AT jianchunyan graphenefarinfrareddryingwheatheattransferandenergybehaviors AT qingzhao graphenefarinfrareddryingwheatheattransferandenergybehaviors AT haiwei graphenefarinfrareddryingwheatheattransferandenergybehaviors AT jiyouan graphenefarinfrareddryingwheatheattransferandenergybehaviors AT kunjiechen graphenefarinfrareddryingwheatheattransferandenergybehaviors AT huanxiongxie graphenefarinfrareddryingwheatheattransferandenergybehaviors |