Experimental and computational investigation of heat transfer in a microwave-assisted flow system

Damilos, Spyridon; Radhakrishnan, Anand N P; Dimitrakis, Georgios; Tang, Junwang; Gavriilidis, Asterios

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 o C. Results from this study provide valuable insights on achievable temperature profiles and energy efficiency of microwave-assisted flow synthesis systems. 2

Citation

Damilos, S., Radhakrishnan, A. N. P., Dimitrakis, G., Tang, J., & Gavriilidis, A. (2019). Experimental and computational investigation of heat transfer in a microwave-assisted flow system. Chemical Engineering and Processing: Process Intensification, 142, Article 107537. https://doi.org/10.1016/j.cep.2019.107537

• Journal Article Type: Article
• Acceptance Date: May 19, 2019
• Online Publication Date: May 23, 2019
• Publication Date: Aug 1, 2019
• Deposit Date: Jun 19, 2019
• Publicly Available Date: May 24, 2020
• Journal: Chemical Engineering and Processing - Process Intensification
• Print ISSN: 0255-2701
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 142
• Article Number: 107537
• DOI: https://doi.org/10.1016/j.cep.2019.107537
• Keywords: Microwave heating; Continuous flow; Heat transfer; Modelling
• Public URL: https://nottingham-repository.worktribe.com/output/2209035
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S0255270118315071?via%3Dihub
• Additional Information: This article is maintained by: Elsevier; Article Title: Experimental and computational investigation of heat transfer in a microwave-assisted flow system; Journal Title: Chemical Engineering and Processing - Process Intensification; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.cep.2019.107537; Content Type: article; Copyright: © 2019 Elsevier B.V. All rights reserved.