Page 315 - Теория кавитации

used in the experimental test bench.

As indicated in the schematic diagram of the VHG (see Figure 1), a pump installation with a large head
(4-6 atm.) Pumps a stream of cold water into the nozzle, and at each transition through the pipe, the temperature
of the liquid heats up by 0.5÷2.0°C.
It should be noted that the pumping unit is the only unit in the composition of VHGD, which consumes
energy from the outside (ie, electrical energy with voltage of 220÷230 V) and therefore, its energy characteristics
are important, when conducting calculations and determining the parameters of energy efficiency (efficiency
factor or ECC) VHG as a whole.

Swirl:
The main function of the swirler is to twist the cool fluid from the pump through the nozzle (choke) that
leads to it and tighten and transfer to the periphery of the cylindrical vortex tube.
The swirl is made in the form of a cochlea (Figure 4), which can also be performed with a screw or spiral
profile of the working chamber, with a constant or narrowing section of the nozzles, with one or more working
chambers, with one or more tangential inputs, with inputs like vortex nozzles and etc.
Thus, the tangential entry (cochlea) had a rectangular shape with a size of 0.8×1.4 cm, and the profile was
made in the form of an Archimedes spiral on experimental studies. Therefore, the swirler can be performed with
a screw or spiral working chambers, with constant or tapering sections of pipes with one or more working
chambers, with one or more tangential inputs and with inputs like vortex nozzles, etc.

а) б)
a - swirl diagram; b - made sample
Figure 4 - Cross-section of the used VHG swirl.

Brake device (cross):
As a brake device, in order to hold the main vortex flow in front of the hot diaphragm, a rod with a cross
pin and a metal disk with holes were located along the pipe (Figure 5).

Figure 5 - Vortex flow brake device (rod with a cross-piece L=70 mm).

In the process of vortex motion and braking, the fluid in the working chamber is activated, heated, and
hot water comes out of the outlet nozzle. Part of the hot water to improve the efficiency of VHG can be
discharged back from its output to the entrance.

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