Microbial Fouling Growth Rule And Impact On Heat Transfer Of Wide Channel Plate Exchanger

Recovering waste heat from renewable non-clean heat source,treated sewage heat pump is of very important engineering application value for environmental protection and energy conservation.The traditional plate heat exchanger has disadvantages of blocking easily and high cleaning frequency when using in sewage heat pump system.Due to relatively wide channel in the treated sewage side,wide channel plate heat exchanger can effectively solve the blockage and reduce the frequency of cleaning.The microbial fouling formed in the treated sewage-wide channel plate heat exchanger is a key factor of decreasing the heat efficiency and increasing the flow resistance.Based on the numerical simulation and experiment,this paper studies the growth rule of microbial dirt and the flow and heat transfer characteristics of the plate heat exchanger.Experimental and numerical methods were employed to explore the growth rule of microbial fouling and heat transfer characteristics of the wide channel plate heat exchanger.This paper introduces the cellular automata theory the basic characteristics of cellular automata.The key to CA modelling is making a CA rules that reflect the nature of the system.Introduced the equations of components of the microbial fouling,author modelling the multi-components cellular automaton by making a CA rules that reflect the nature of microbial fouling formed under treated sewage condition.Obtained the density distribution of microbial fouling,and able to show a comparison with experimental results.A new scale model experiment channel system were established in this study.The experiment were conducted to study the initial period growth rule of the microbial fouling.and the influence of the stream scour angle on microbial fouling growth.Three stages has been found in microbial fouling initial growth period which are rapid growth,attachment and regrowth.The experiment results showed significant influence of the stream scour angle on microbial fouling growth.Classical porous medium model was employed to fitting thermal resistance of the microbial fouling.Variation of microbial fouling thickness,thermal conductivity and thermal-conduction resistance were obtained.Numerical simulating software Fluent was employed to study heat transfer and flow characteristics of wide channel plate heat exchanger,and velocity,temperature,pressure distribution were obtained.Microbial fouling thermal resistance was used in simulation to study the impact that microbial fouling have on heat transfer of wide channel plate exchanger.The simulation results showed a reduction of about 21% in heat exchange performance in the end of biofouling initial growth period.