Modeling and simulation of the transient response of temperature and relative humidity sensors with and without protective housing.
Based on the necessity for enclosure protection of temperature and relative humidity sensors installed in a hostile environment, a wind tunnel was used to quantify the time that the sensors take to reach equilibrium in the environmental conditions to which they are exposed. Two treatments were used: (1) sensors with polyvinyl chloride (PVC) enclosure protection, and (2) sensors with no enclosure protection. The primary objective of this study was to develop and validate a 3-D computational fluid dynamics (CFD) model for analyzing the temperature and relative humidity distribution in a wind tunnel using sensors with PVC enclosure protection and sensors with no enclosure protection. A CFD simulation model was developed to describe the temperature distribution and the physics of mass transfer related to the airflow relative humidity. The first results demonstrate the applicability of the simulation. For verification, a sensor device was successfully assembled and tested in an environment that was optimized to ensure fast change conditions. The quantification setup presented in this paper is thus considered to be adequate for testing different materials and morphologies for enclosure protection. The results show that the boundary layer flow regime has a significant impact on the heat flux distribution. The results indicate that the CFD technique is a powerful tool which provides a detailed description of the flow and temperature fields as well as the time that the relative humidity takes to reach equilibrium with the environment in which the sensors are inserted.
Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, Viçosa, Brazil.
Keller Sullivan Oliveira
KS
Rocha
Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, Viçosa, Brazil.
José Helvecio
JH
Martins
Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, Viçosa, Brazil.
Marcio Arêdes
MA
Martins
Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, Viçosa, Brazil.
Ilda de Fátima Ferreira
Ide F
Tinôco
Departamento de Ingeniería de Alimentos, Universidad Nacional de Colombia, Medellín, Colombia.
Jairo Alexander Osorio
JA
Saraz
Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, Viçosa, Brazil.
Adílio Flauzino
AF
Lacerda Filho
Departamento de Engenharia Agrícola, Universidade Federal de Viçosa, Viçosa, Brazil.
Luiz Henrique Martins
LH
Fernandes
D000383:Agriculture / Q000295:instrumentation; D003198:Computer Simulation; D004867:Equipment Design; D005511:Food Handling / Q000295:instrumentation; D006813:Humidity; D057446:Hydrodynamics; D008956:Models, Chemical; D011143:Polyvinyl Chloride / Q000737:chemistry; D013696:Temperature; D013821:Thermometers; D014919:Wind
D011143:Polyvinyl Chloride