Analyses of thermal performance and pressure drop in a plate heat exchanger filled with ferrofluids under a magnetic field. (1st June 2021) - Zheng, Dan
Highlights: Thermal performance of a plate heat exchanger under a magnetic field is studied. Heat transfer performance is significantly improved by applying a magnetic field. Pressure drop grows negatively for a vertical magnetic field. Average Nusselt number under magnetic field arrangements deviates below 3.4%. Pressure drop is reduced 10% with a side-by-side vertical magnet arrangement. Abstract: This paper experimentally investigates the effect of various magnetic fields on the performance of a plate heat exchanger filled with ferrofluids. Spherical nanoparticles Fe3 O4 with an average diameter of 20 nm are dispersed into DI-water to synthesize the ferrofluid. Thermal performance and flow characteristics of the ferrofluid with 0.1% particle concentration are investigated based on various arrangements of magnets outside the plate heat exchanger. Effects of magnetic field strength and distribution are thoroughly studied concerning the performance of the heat exchanger with various ferrofluid flow rates. Results indicate that with a vertical arrangement of two magnets side by side outside the sidewalls, 21.8% increase in average Nusselt number and 10.0% reduction in average pressure drop are achieved compared to the cases without a magnetic field. Novel configurations of magnets are first discussed in a plate heat exchanger. Ferrofluid flow control is achieved under a measurable magnetic field strength and different flow rates. It is well known that enhancement of thermal performance in the plate heat exchanger is accompanied with a reduction of resistance loss. Deposition of magnetic particles and blockage in the channel of the plate heat exchanger will also be weakened based on results from this research.