Kinetics of nonisothermal adsorption by biporous adsorbents. Communiication 5. Analytical description of the temperature curves and determination of mass- and heat-transfer parameters

Author(s):  
A. G. Bezus ◽  
A. M. Voloshchuk ◽  
V. A. Gorlov ◽  
M. M. Dubinin ◽  
A. Zikanova ◽  
...  
2010 ◽  
Vol 48 (5) ◽  
pp. 741-746 ◽  
Author(s):  
V. G. Zverev ◽  
V. A. Nazarenko ◽  
S. V. Pan’ko ◽  
A. V. Teploukhov

Author(s):  
Xavier Tardif ◽  
Vincent Sobotka ◽  
Nicolas Boyard ◽  
Philippe Le Bot ◽  
Didier Delaunay

Injection molding is the most used process for thermoplastic part manufacturing. This process is commonly divided into four steps: injection, packing, cooling and ejection. During the packing step, an amount of material gets into the mold cavity to compensate for shrinkage of the polymer mainly due to the crystallization. Once the gate is frozen, polymer is subjected to isochoric cooling while the pressure of the polymer is higher than atmospheric pressure. Improving the quality of the injected part requires prediction of the shrinkage, warpage and residual stress and pressure impacts deeply on the morphology and consequently on the shape of the final part. The pressure decrease during the isochoric phase also determines the ejection time. However, description of the behavior of the polymer during packing and isochoric steps needs an accurate model that considers coupling between heat transfer and crystallization and also a good knowledge of the behavior (specific volume and crystallization kinetics) of the polymer under high pressure. Some studies have already underlined the influence of shear rate on the kinetics of crystallization. Here, based on a pressure analysis and an experimental-numerical comparison, we confirm crystallization is strongly coupled to flow history.


2018 ◽  
Vol 70 ◽  
pp. 02016
Author(s):  
Joanna Wilk ◽  
Sebastian Grosicki ◽  
Krzysztof Kiedrzyński

In the paper the authors present the facility for model investigations of heat/mass transfer in the exchanger characterised by small dimensions. Determination of heat transfer coefficients is an important issue in the design of mini heat exchangers. The built facility enables measurements of mass transfer coefficients with the use of limiting current technique. The coefficients received from the experiment are converted into heat transfer coefficients basing on the analogy between mass and heat transfer. The exchanger considered consists of nine parallel minichannels with a square cross-section of 2mm. In real conditions during the laminar flow through the minichannels the convective heat transfer occurs. Analogous conditions are maintained during the model mass transfer experiment. The paper presents the experimental facility and the preliminary results of measurements in the form of voltammograms. The voltammograms show the limiting currents being the base of mass transfer coefficient calculations.


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