الفهرس 
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Abstract
The pulsating flow is characterized by periodic fluctuations of the mass flow rate and pressure. Experimenjts were carried out to evaluate the use of pulsation as a heat transfer augmentation technique in the fully developed turbulent flow through pipes.
Experiments were conducted to investigate the effect of downstream pulsation upon heat transfer characteristics foe fully developed turbulent flow through heated circular pipe. The experiments were conducted in an electrically heated horizontal brass tube under constant heat flux, with air as working fluid. The experiments were carried out for Reynolds number range from 27900 to 58900 and pulsating frequency range from 45 to 145 Hz. The results showed that the relative average Nusselt number for flow without pulsation is affected by both Reynolds number and frequency, and the enhancement in heat transfer depends on both frequency and Reynolds number.
For pulsation frequency of f=45 HZ, the relative average Nusselt number increases to about 67.2%, then it increases gradually up to 82.3% at Re=51500.at Re=58900 an enhancement of about 64.2% in the relative average Nusselt number is obtained. For Reynolds number 51500, the maximum enhancement in the average Nusselt number is obtained at frequency of 45HZ, with obout 82.3%, and it decreases gradually for the frequency range 90>f96.7 HZ, then it is slightly decreases for the pulsating frequency range of 135> f>145 HZ.
The experimental results of the relative average Nusselt number of the turbulent pulsating flow, are plotted in terms of the pulsation frequency and Reynolds number to discuss their effects on heat transfer and finding out thhhe proper experimental correlation. The results are evaluated and analyzed in terms of the bursting phenomenon that associated with turbulent flow, and the results show that the eat transfer was highly affected by Reynolds number while it was slightly affected by the pulsating frequency.