Self-excited Pulsed Jet Research Articles

Orthogonal experimental research on the structural parameters of a self-excited pulsed cavitation nozzle

A variety of geometric sizes of a self-excited pulsed jet such as the diameter of the suction and discharge nozzle, jet chamber length and diameter, and the collision angle are the main structural parameters. Under certain operating conditions at a given fluid flow rate, target space, and dynamic head, the jet strike force amplitude and frequency were significantly influenced by these structural sizes. Twenty five group orthogonal experiments were designed to explore the jet dynamic performance with structural sizes to find which group was the best combination. The experiment employed five levels of the diameter of the suction and discharge nozzles, three levels of the chamber diameter, and five levels of the length of the chamber and collision angles. Experimental results showed that the suction nozzle diameter was the most important parameter influencing the jet performance. The next was discharge nozzle diameter. The other three sizes of chamber diameter and length, and collision angle had the similar effect on the self-excited pulsed jet. The results can have guiding significance for the design of self-excited pulsed cavitation nozzles.

Experimental research on performance parameters of a self-excited pulsed jet device

The self-excited pulsed jet is characteristically efficient and inexpensive. To develop an optimal pulsed jet, the structural and operating parameters affecting its peak hitting power were studied. The optimal range of cavity length and diameter, the areal ratio of the bottom and top nozzles, the bottom nozzle length, and the target distance and working pressure were all determined.

Erosion Experiment of Self-Excited Oscillation Pulsed Jet

In order to improve the erosion effect of jet under submergence condition, experimental studies of erosion generated from the self-excited pulsed jet was carried out by using developed self-excited oscillation nozzle. The erosion volume and depth of pulsed jet were measured and taking mortar block as an erosion part. The results were that the standoff has significant influence on erosion effect. The erosion volume firstly decreases with increases in cavity length and then increases to a peak value. Erosion volume of pulsed jet is significantly higher than that of continuous jet, the erosion depth of two jet has slight difference.

Time domain analysis on impulsion performance of self-excited pulsed jet device

By nondimensional analysis and test, the change laws of impact force time-domain eigenvalues with the variation of structure and operating parameters of self-excited pulsed jet device were studied so as to analyze the mutual relations between the time-domain eigenvalues of self-excited pulsed jet device impact force and parameters(operation and structure), pulse characteristics. The pulse jet impact and effect figure, the relation curve between the time-domain eigenvalues and parameters(operation and structure) are obtained. The results show that the change laws of impact force time-domain eigenvalues are various with different structure and operating parameters; pulse index C and peak index I can serve as indicators to evaluate the pulse effect, the pulse effect is better when the value changes between 1 and 2; there is an optimal ratio range of structure and operating parameters under certain conditions. The results provide a basis for optimizing the parameter selection of self-excited pulsed jet.

Experimental Study on Device Parameters of Self-Excited Pulsed Jet to the Performance

In order to study the influence of the structural and operating parameters on device performance of the self-excited pulsed jet in low-press and Amount-flux, a great deal of experiments on structural and operating parameters of the self-excited pulsed jet was carried out by independently developed testing system. Under the certain upper nozzle diameter and cavity diameter, the changes of the lower nozzle diameter and cavity length and working pressure have an effect on the hitting power of the pulsing jet and pulsing effect. Experimental results showed that for the different lower nozzle diameter and under each working pressure the influence of the cavity length changes on the hitting power is different, there is the optimal range of cavity length and working pressure while the lower diameter is fixed, and with the increase of the lower nozzle diameter, the range of the optimal cavity length and working pressure also has a gradually increasing trend.