A review on simultaneous determination of thermal diffusivity and heat transfer coefficient

Erdoğdu, Ferruh

doi:10.1016/j.jfoodeng.2007.10.019

Cited by 47 publications

(44 citation statements)

References 32 publications

(43 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It must be observed that different α and h pairs can describe the cooling kinetics (Erdogdu 2008), since the objective function may have more than one minimum point. This is a problem which occurs in many optimization processes as, for example, in nonlinear regression.…”

Section: Constant Thermal Diffusivitymentioning

confidence: 99%

“…Although analytical models are still used (Becker and Fricke 2004;Erdogdu 2005;Erdogdu 2008;Kumar et al 2008;Cuesta and Lamúa 2009;Raval et al 2011), in the recent years many works use numerical solutions to describe the cooling kinetics of agricultural products. Campanõne et al (2002) used an implicit finite-difference scheme to describe the simulation of food refrigeration.…”

Section: Introductionmentioning

confidence: 99%

“…According to Silva et al (2011), the best model in the representation of the cucumber's shape was the ellipsoid, but the time demanded in its optimization was about 66 times greater than the time for the infinite cylinder. As observed by Erdogdu (2008), the simultaneous determination of the thermal diffusivity and convective heat transfer coefficient is difficult to accomplish because there may be several pairs of these parameters for which the solution of the diffusion equation is fitted to a set of experimental data. In other words, the objective function may have several local minima.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Calculation of the convective heat transfer coefficient and thermal diffusivity of cucumbers using numerical simulation and the inverse method

Silva

2012

J Food Sci Technol

View full text Add to dashboard Cite

Cooling of fruits and vegetables, immediately after the harvest, has been a widely used method for maximizing post-harvest life. In this paper, an optimization algorithm and a numerical solution are used to determine simultaneously the convective heat transfer coefficient, h H , and the thermal diffusivity, α, for an individual solid with cylindrical shape, using experimental data obtained during its cooling. To this end, the one-dimensional diffusion equation in cylindrical coordinates is discretized and numerically solved through the finite volume method, with a fully implicit formulation. This solution is coupled to an optimizer based on the inverse method, in which the chi-square referring to the fit of the numerical simulation to the experimental data is used as objective function. The optimizer coupled to the numerical solution was applied to experimental data relative to the cooling of a cucumber. The obtained results for α and h H were coherent with the values available in the literature. With the results obtained in the optimization process, the cooling kinetics of cucumbers was described in details.

show abstract

Section: Constant Thermal Diffusivitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Calculation of the convective heat transfer coefficient and thermal diffusivity of cucumbers using numerical simulation and the inverse method

Silva

2012

J Food Sci Technol

View full text Add to dashboard Cite

show abstract

“…Este proceso demandará un mayor consumo de agua y energía, produciendo un mayor volumen de efluentes y un mayor costo e impacto ambiental si no se lleva a cabo un adecuado control y optimización del proceso, ocasionando problemas relacionados con: i) la calidad sensorial del producto como color, textura y sabor, y ii) con la calidad nutritiva como pérdidas de vitaminas, azúcares y minerales (Arboleda et al, 2010;Augusto et al, 2012;Xin et al, 2015;Xu et al, 2015). El control y optimización adecuados del proceso de escaldado exige el conocimiento de los valores del coeficiente convectivo de transferencia de calor (h), sin embargo, para muchos procesos térmicos no se encuentran disponibles estos valores, ya sea porque no existen investigaciones o porque la irregularidad del alimento exige técnicas muy rigurosas de cálculo (Fricke y Becker 2002;Erdoğdu, 2008).…”

Section: Introductionunclassified

Determinación del Coeficiente Convectivo de Transferencia de Calor del Proceso de Escaldado de Zapallo (Cucurbita maxima)

et al. 2017

View full text Add to dashboard Cite

*Autor a quien debe ser dirigida la correspondenciaRecibido Sep. 2, 2016; Aceptado Nov. 14, 2016; Versión final Feb. 17, 2016, Publicado Jun. 2017 Resumen Se determina el coeficiente convectivo de calor del escaldado de zapallo (Cucurbita maxima) a temperaturas de 70ºC±1, 80ºC±1 y 90ºC±1 y una duración de 320 segundos. La medición de la temperatura del centro geométrico de muestras en forma triangular se realizó con termopares tipo K referencia NIUSB-TC01 (National Instruments). Para la solución del modelo matemático se empleó el método de elementos finitos con la ayuda del software COMSOL Multiphysics 3.5. Para determinar el valor del coeficiente convectivo de calor se resolvió un problema de optimización minimizando el error medio relativo entre los valores de temperatura experimentales y temperatura simulados del centro geométrico. Los resultados del coeficiente convectivo fueron 390±17 W/m 2°C para 70°C, 455±11 W/m 2°C para 80ºC y 535±13 W/m 2°C para 90°C. Además, los porcentajes del error medio relativo obtenidos se encontraron por debajo del 5%, lo cual indica buena predicción del modelo matemático utilizado. Palabras clave: transferencia de valor; conducción; convección; escaldado; Cucurbita maxima Determination of the Convective Heat Transfer Coefficient of the Blanching Process of Cucurbita maxima AbstractThe convective heat transfer coefficient of the blanching process of Curcuma maxima at different temperatures (70°C±1, 80°C±1 and 90°C±1) and duration of 320 seconds were determined. The temperature of the geometric center of triangular samples was measured using reference K-type thermocouples NIUSB-TC01 (National Instruments). The mathematical model was solved with the finite element method using the software COMSOL TM Multiphysics 3.5. To find the value of the convective heat transfer coefficient an optimization problem was solved by minimizing the relative average error, between the values of the experimental temperature and the simulated temperature of the geometric center. The results of the convective heat transfer coefficient were 390±17 W/m 2°C to 70°C, 455±11 W/m 2°C for 80°C and 535±13 W/m 2°C to 90°C. In addition, the percentages of relative average error obtained are found below 5%, which indicates good accuracy of the mathematical model used.

show abstract

“…En décadas pasadas resolver este tipo de ecuaciones tenía un grado de complejidad y dificultad muy alto, esta herencia ha permanecido en los ingenieros de procesos actuales, no obstante, los avances en la tecnología computacional han facilitado la programación de cálculos más complejos y con tiempos de cómputo más cortos, lo cual permite resolver los problemas de tratamientos térmicos con mejor acercamiento a la realidad (Erdoğdu, 2008).…”

Section: Introductionunclassified

Modelado Matemático de la Transferencia de Calor del Proceso de Escaldado de Zanahoria (Daucus carota L.)

et al. 2017

View full text Add to dashboard Cite

ResumenLos objetivos del presente trabajo fueron modelar el proceso de escaldado de zanahoria y determinar el coeficiente convectivo de transferencia de calor del proceso. El escaldado se llevó a cabo en un baño de agua con temperaturas de 70±1°C, 80±1°C y 90±1°C. Las temperaturas se midieron utilizando termopares tipo J con transmisor NI-USB-TC01 unido a la interfaz LabVIEW-2012. Se desarrolló un modelo matemático de transferencia de calor en estado no estacionario el cual fue resuelto por el método de elementos finitos asistido por COMSOL Multiphysics 3.5. La zanahoria fue considerada de forma cónica y con dos capas concéntricas de propiedades térmicas diferentes. Los resultados obtenidos con COMSOL son similares a los valores de temperaturas experimentales. Además los valores de los coeficientes convectivos se encuentran entre 433 y 643 W/m 2°C . Se concluye que el modelo desarrollado predice la temperatura con errores menores al 5%. Palabras clave: escaldado; convección; ley de Fourier; elementos finitos; modelado Mathematical Modeling of Heat Transfer of Blanching Process of Carrot (Daucus Carota L.) AbstractThe objectives of this research were to model the blanching process of carrot and to determine the convective heat transfer coefficient of the process. Blanching is carried out in water at temperatures of 70±1°C, 80±1°C and 90±1°C. The temperatures were measured using J-type thermocouples with a NI USB-TC01 transmitter attached to the interface LabVIEW-2012. A mathematical model of heat transfer in unsteady state was developed, and was solved by the finite element method assisted by COMSOL Multiphysics 3.5. The carrot sample was considered like cone-shaped with two concentric layers of different thermal properties. The numerical results obtained with COMSOL are similar to the values of the experimental temperatures. Also the values of the convective heat transfer coefficients were between 433 and 643 W/m 2°C . It is concluded that the proposed model predicts the temperature with errors less than 5%.

show abstract

A review on simultaneous determination of thermal diffusivity and heat transfer coefficient

Cited by 47 publications

References 32 publications

Calculation of the convective heat transfer coefficient and thermal diffusivity of cucumbers using numerical simulation and the inverse method

Calculation of the convective heat transfer coefficient and thermal diffusivity of cucumbers using numerical simulation and the inverse method

Determinación del Coeficiente Convectivo de Transferencia de Calor del Proceso de Escaldado de Zapallo (Cucurbita maxima)

Modelado Matemático de la Transferencia de Calor del Proceso de Escaldado de Zanahoria (Daucus carota L.)

Contact Info

Product

Resources

About