2.4.4       The exploding egg effect

Consider the example ..\Heating\Cwgheat\exegg.pro. It concerns an egg heated in a microwave oven. Both the oven and the egg are taken from the standard UDO library. Thus the scenario can easily be modified using Select Object option ( button). Remember that this example is composed of Biphased Objects and thus after modification you should change the drawing phase of QW-Editor to Draft and back to Final, to obtain optimum meshing of the structure.

First run the exegg.pro example in its original form. After about 20000 iterations we open Results window ( button in Results tab of QW-Simulator) and obtain the |S11| characteristic as presented in Fig. 2.4.4-1. It can be seen that the oven resonates at 2.356 GHz.

Now excite the considered oven at the resonant frequency (example exeggs.pro). After about 20000 iterations open the 2D/3D Fields Distribution window with  button from 2D/3D Fields tab of QW-Simulator. The appearing window shows the display of dissipated power density pd in a plane across the egg. The display is in dynamic mode enabling plane envelope calculation. For the purpose of calculating the distribution of time-maximum power density, press  button in Envelope tab of 2D/3D Fields Distribution window. When the image stabilises we obtain the picture as presented in Fig. 2.4.4-2. It can be clearly seen that the dissipated power concentrates in the centre of the egg. In the physical experiment, evaporation of water overheated in that area would cause the explosion of the egg – an experience quite memorable to many who tried it.

Fig. 2.4.4-1 |S11| versus frequency obtained in exegg.pro example.

Fig. 2.4.4-2 Distribution of the maximum of dissipated power density inside the egg heated in a microwave oven of exeggs.pro example.