Numerical and Experimental Study on Heat Transfer Process Under Microwave Irradiation Using Reflector to Enhance Energy Absorption Rate

Author(s):  
M. Kumja ◽  
Ng Kim Choon ◽  
Wai Soong Loh ◽  
Christopher Yap

With the energy saving concerns, microwave heating method becomes much attention in heating process of various applications. Depending on applicator geometry design, type of work load, and position in a microwave heating system, it can save energy 20% to 40% more than the energy consumed by a conventional heating method. However, it is difficult to achieve this energy saving for low dielectric constant workload that cannot perform as a self-dielectric resonator (DR) load. This paper aspires to propose a new method of inserting reflector into the low dielectric constant load to enhance energy absorption rate under the microwave irradiation process. The spatial electromagnetic fields (E-field and H-field) patterns of this workload and applicator were simulated with the commercial HFSS software. By using the Poynting vector theorem, the dissipation power intensity can be calculated from the electromagnetic field and it is integrated to the second order heat transfer equation. The numerical temperature distribution result was resemblance with the experimental result. From both numerical and experimental results, the energy absorption rate of workload can be improved obviously by using a reflector as compared to the rate without using the reflector for low dielectric constant.

1999 ◽  
Vol 565 ◽  
Author(s):  
Y. Shimogaki ◽  
S. W. Lim ◽  
E. G. Loh ◽  
Y. Nakano ◽  
K. Tada ◽  
...  

AbstractLow dielectric constant F-doped silicon oxide films (SiO:F) can be prepared by adding fluorine source, like as CF4 to the conventional PECVD processes. We could obtain SiO:F films with dielectric constant as low as 2.6 from the reaction mixture of SiH4/N2 O/CF4. The structural changes of the oxides were sensitively detected by Raman spectroscopy. The three-fold ring and network structure of the silicon oxides were selectively decreased by adding fluorine into the film. These structural changes contribute to the decrease ionic polarization of the film, but it was not the major factor for the low dielectric constant. The addition of fluorine was very effective to eliminate the Si-OH in the film and the disappearance of the Si-OH was the key factor to obtain low dielectric constant. A kinetic analysis of the process was also performed to investigate the reaction mechanism. We focused on the effect of gas flow rate, i.e. the residence time of the precursors in the reactor, on growth rate and step coverage of SiO:F films. It revealed that there exists two species to form SiO:F films. One is the reactive species which contributes to increase the growth rate and the other one is the less reactive species which contributes to have uniform step coverage. The same approach was made on the PECVD process to produce low-k C:F films from C2F4, and we found ionic species is the main precursor to form C:F films.


2020 ◽  
Author(s):  
Vedanki ◽  
Chandrabhan Dohare ◽  
Pawan KumarSrivastava ◽  
Premlata Yadav ◽  
Subhasis Ghosh

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