Vibration Tube. Constant Heat Flux Conditions Fouling Characteristics Of Experimental Research

Heat exchangers are used widely in industry. Fouling problem exits in more than 95 percent of heat exchangers, it declines the performance of heat transfer surface and increase flow resistance, therefore induce a series of economic loss, and fouling entity is one of the most difficult problems in heat transfer enhancement.This paper establishes experiment platform on the round tube fouling ,uses manual hard water, which is made of calcium chloridize, sodium bicarbonate and sodium hydroxide, as experimental matter, and measures the stillness and the vibration pipe's fouling growth character and vibration heat transfer enhancement in the condition of constant heat flux.The experiment platform on stillness round tube fouling is established to test the law of fouling resistance and time. The results shows that fouling grow curve is representative asymptote. Besides, the fouling growth rate increases while surface temperature increases.The experiment platform on vibration round fouling is established to obtain fouling growth curves when the vibration amplitude and frequency is different and the expression between the asymptotic fouling thermal resistance and vibration Reynolds number. The results shows that the fouling grow curve is representative asymptote, also, and that the increase of vibration Reynolds number should reduce the asymptotic fouling resistance in exponential form, and that the vibration asymptotic fouling resistance is less than stillness asymptotic fouling resistance when the conditions are sameness (the concentration of the calcium chloridize and sodium bicarbonate, the pH value, the heated power, the fluid velocity across the pipe).The fouling experiment is done when the tube changes from vibration to stillness to obtain the fouling growth curve in the whole process. The experimental results suggest that the final fouling thermal resistance increase 35 percent than that when the pipe stops vibrating.. It shows that the denudation force of the vibration pipe is more than the stillness pipe, and furthermore validates that vibration can prevent fouling well.This paper also investigates the vibration heat transfer enhancement, measures the relation between the average heat transfer coefficient and the vibration frequency, the amplitude, and gains the drafted expression of heat transfer. Either the frequency is high or low, with the same vibration Reynolds number, between the high frequency low amplitude vibration and the low frequency high amplitude one, the former influence the heat transfer enhancement more intensively than the latter.This paper analyses the model of dissolution and desquamation of the vibration pipe's fouling, the results suggest that the enhancement of mass transfer because of the vibration of round tube should accelerate the...