1. Experimental and computational investigation of heat transfer in a microwave-assisted flow system
- Author
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Asterios Gavriilidis, Spyridon Damilos, Georgios Dimitrakis, Junwang Tang, Anand N. P. Radhakrishnan, Damilos, Spridon, Radhakrishnan, Anand, Dimitrakis, Georgios, Tang, Junwang, and Gavriilidis, Asterios
- Subjects
Absorption (acoustics) ,Work (thermodynamics) ,Optical fiber ,Materials science ,General Chemical Engineering ,Flow (psychology) ,Energy Engineering and Power Technology ,02 engineering and technology ,Industrial and Manufacturing Engineering ,Modelling ,law.invention ,020401 chemical engineering ,law ,Electric field ,Heat transfer ,Continuous flow ,Tube (fluid conveyance) ,0204 chemical engineering ,Process Chemistry and Technology ,General Chemistry ,Mechanics ,021001 nanoscience & nanotechnology ,Microwave heating ,0210 nano-technology ,Microwave - Abstract
Microwave technology is gaining popularity as a tool for chemical process intensification and an alternative to conventional heating. However, in flow systems non-uniform temperature profiles are commonly encountered and hence methods to characterise and improve them are required. In this work, we studied the effects of various operational parameters - microwave power, inlet flow rate, tube orientation and pressure - on the electric field and temperature profiles of water flowing in a PTFE tube (2.4 mm internal diameter), placed in a commercial single-mode microwave applicator. A finite element model was developed to estimate the longitudinal temperature profiles and the absorbed microwave power, while in situ temperature monitoring was performed by a fibre optic probe placed at multiple locations inside the tube. The water temperature inside the tube increased by increasing the microwave power input and temperature profiles stabilised beyond 20 W, while the percentage absorbed microwave power showed the inverse trend. When changing the tube orientation or decreasing the inlet flow rate, microwave absorption decreased significantly. When the pressure was increased to 2.3 bara, water temperature increased by ∼20 °C. Results from this study provide valuable insights on achievable temperature profiles and energy efficiency of microwave-assisted flow synthesis systems.
- Published
- 2019