Z. Taghizadeh Tabari - Chemical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
S. Zeinali Heris - Chemical Engineering Department, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran

Increasing the Plate Heat Exchanger efficacy is a method of reducing energy consumption in pasteurization and sterilization of milk in dairy industries. In order to enhance the heat transfer capability of water as a hot stream in Plate Heat Exchanger, Multi-walled Carbon Nanotubes (MWCNT) were added into the water. Two step method is used to produce these nanofluids with water based fluid. An Experimental setup is designed and manufactured to measure the heat transfer a key parameter for convective heat transfer. This system has two individual loops for hot and cold fluids. Reynolds Number range for hot stream was between 90 and 250 and boundary condition of constant temperature for heater section is selected. The Experimental results clearly indicate that heat transfer coefficient of pure water is increased by addition of MWCNT with weight concentration of less than 1% wt. By increasing the weight concentration of nanoparticles, the heat transfer coefficient is increased. This augmentation intensifies at higher Peclet numbers which shows more effective presence of these nanoparticles at high flow rates of nanofluids. Moreover at a constant weight concentration both of the heat transfer coefficient is increased as well. Augmentation of the heat transfer capability results in much heat exchange with milk fluid in a short time thus before fouling occurs in plates of exchanger, pasteurization of milk and production of the products will be easier.

nanofluid, Plate heat exchanger, Heat transfer enhancement, dairy industries