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- Researchers sconveys nonuniform heating of liquids in a microwave change the thermal behavior of liquids and see why microwaving lifts are different from other methods.
- Using cut-off wave theory, conventional glass has been modified in a simple and efficient way to distribute heat evenly. in a common home panel microwave oven.
The convenience of boiling water in the microwave comes with commercial advantages. First, when the water is not heated long enough, it will not heat up evenly, and secondly, using the wrong material can cause harmful explosions.
Heating water in a microwave is unlike heating water on the stove. With the stove, the liquid towards the bottom of the kettle first heats up, becomes denser and moves to the top, while a colder part of the water moves closer to the source of the boiler. heat. This process is called convection and defines the uniform temperature that comes from heating lifts on the stove.
In contrast, when water is heated in a microwave, electromagnetic waves in the oven heat water molecules at random spots. However, when a water vessel is placed in the microwave, the electric field that acts as a heat source inside the microwave heats the entire trap at the same time, he explained. researchers at China University of Electronic Science & Technology. In this case, the liquid at the top of the glass is much hotter than the liquid at the bottom.
The researchers, who studied nonuniform heating of liquids in a microwave, offer a solution for evenly heating water in a microwave. Building out of wavelength theory, they designed silver plating to go on the edge of glass. In wavelength theory, electromagnetic waves below the cutting frequency will cause a reduction in the wavelength.
The silver-plated cup helps lifts heat through microwave uniforms.Baoqing Zeng
The modified glass is placed in the center of the ceramic plate, far away from the microwave cave wall. The silver edge on the glass creates a buffer against the impact of the microwave at the surface of the liquid, the researchers noted. The silver edge acts as a guide for the waves and reduces the electric field at the top of the glass. As a result, the waters at the top of the glass are not heated by the microwave. This wavelength cutting method creates a convection process similar to traditional stove heating, they explained, leading to a more integrated temperature.
Placing metals, such as silver, in the microwave can be dangerous to see when carrying electricity. The metals placed in the microwave contain electricity, which exposes microorganisms. Without enough material in the microwave to absorb the visible microwave, arcing (sparks) can occur between the metal object and part of the microwave. The researchers noted, however, that metal structures resembling fine geometry can avoid ignition, and that this arrangement has been used safely for microwave steam pots and rice cookers.
“After carefully designing the metal structure to the appropriate size, the metal edge, which is prone to ignition, is positioned at weak field strength, where it can avoid mitigation altogether, and so it’s still safe, ”said Baoqing Zeng, one of the paper’s authors and professor of electronic science and engineering at UESTC.
Going forward, the research group is considering other ways to improve absenteeism in solid foods, although the current methods are too expensive for practical use, they said. They are also working with a microwave manufacturer to commercialize their microwave facilities for liquids.
Journal Reference
Peiyang Zhao, Weiwei Gan, Chuanqi Feng, Zhongxing Qu, Jianlong Liu, Zhe Wu, Yubin Gong, Baoqing Zeng. “Multiphysics analysis for unusual heat convection in microwave heating fluids.” AIP Advances, 2020; 10 (8): 085201 DOI: 10.1063 / 5.0013295