Study On The Scaling Law Of CaCO₃ On The Surface Of Annular Flow Heat Transfer

The fouling will prevent the heat transfer from the heat exchange surface,resulting in the reduction of heat transfer efficiency of the heat exchange surface and even causing damage to the equipment.By studying the fouling law on the heating rod surface,we can provide a strong theoretical basis for the use and optimization of the collector scaling device in the field,and also provide guidance for the heat exchange equipment.In this paper,we establish the physical model of three-dimensional annular flow through the small scale collection equipment of the group,and use FLUENT software to numerically simulate the fouling process on the surface of heating rod using UDF programming;for fouling,the nucleation induction period is also very important,and through reviewing the literature,we found that few scholars have combined the simulation of nucleation induction period and fouling period,so in this paper,during the simulation process Therefore,in this paper,we consider the influence of nucleation induction period of fouling and use COMSOL software to simulate nucleation induction period,and then combine the two results to make the simulation closer to the actual situation in the field;secondly,we build a loop experimental platform to conduct fouling experiments to verify the correctness of the simulation results;finally,we use numerical simulation to study the fouling law under different operating parameters.Considering the simulation of fouling during the induction period and the experimental results yielded the following results:(1)The fouling induction period will gradually decrease as the power of the heating rod increases;the induction period time will gradually increase as the flow rate increases;the induction period will decrease as the fluid concentration increases;and the induction period time will decrease as the initial temperature increases.(2)In the direction of fluid flow,the temperature gradually increases and the concentration gradually decreases;at the same position,the temperature of the scale surface decreases with the increase of scaling time;at the same moment,along the flow direction of the heat exchange surface,the temperature of the scale surface has a tendency to increase;with the change of time,the rate of fouling generation is gradually decreasing,the rate of fouling stripping is increasing,while the net deposition rate is gradually decreasing;the resistance of fouling thermal resistance is increasing along the flow direction.(3)The higher the inlet temperature,the greater the amount of fouling on the heat exchange surface;with the increase of heating rod power,the amount of fouling increases;the greater the solution concentration,the greater the amount of fouling deposition;the greater the inlet flow rate,the greater the rate of fouling stripping and the less the amount of fouling deposition.