Convection regime between canopy and air in a greenhouse

Scientia Agricola

Roberto Terumi Atarassi¹  Marcos Vinicius Folegatti²  René Porfírio Camponez Do Brasil¹ 

[1] ,USP ESALQ Depto. de Engenharia RuralPiracicaba SP ,Brasil

关键词: heat flux;    leaf;    aerodynamic resistance;    fluxo de calor;    folha;    resistência aerodinâmica;   

DOI  :  10.1590/S0103-90162006000100012

来源: SciELO

【 摘 要 】

The use of covering materials in protected environments modifies the air movement close to the crop canopy compared to external environment, which changes the heat and mass transfer between canopy and air. Several researches have been made in greenhouses to estimate mass and heat flux using dimensionless numbers to characterize the type of convection (forced, free or mixed). The knowledge of which one is dominant allows simplifications and specific approaches. The dominant convection regime between canopy and air was determined in a naturally ventilated greenhouse cropped with sweet pepper. Forced convection was predominant, representing more than 70% of the time. During daytime, an increase of mixed convection was observed. It is thus appropriated the use of models that include both forced and mixed convection in the studies of mass and heat exchanges in canopy - air interface.

【 授权许可】

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