# Design of a New Supersonic Shock Wave Generator and Application in Power Generation
## 2 Design of a New Shock Wave Generator  
This study proposes a new shock wave generator [22], comprising a high-pressure storage tank and a balanced valve stem (as shown in Figure 3). The gas storage space is arranged on the outer ring inside the high-pressure storage tank and is joined to a high-pressure gas inlet unit by a pin. An inner cylinder is set in the center of the gas storage tank to connect it to the outside world, and there is an inlet in front of the inner cylinder to connect it to the gas storage space. A homogeneous jet nozzle is arranged at the front end of the high-pressure storage tank, and the front end of the nozzle is joined to a shock  
Figure 1: Structure of the traditional shock wave switch.  
Figure 2: Metal partitions used in the traditional shock wave generation device. (**a**) Metal partitions with different notch depths. (**b**) Impact burst.  
tube by a pin. The balanced valve stem is in the inner cylinder of the high-pressure storage tank, with a front and rear sealed part. The rear end is jointed with a stem driving device by a pin, which can drive the valve stem forward and backward in the inner cylinder by gas pressure.  
This supersonic shock wave generator works as follows: (1) when the high-pressure gases enter the front and rear sealed parts, due to their equal stressed area and acting force, the balanced valve stem creates static balance, which can effectively prevent the high-pressure gas from flowing into the homogeneous jet nozzle and shock tube (Figure 4a); (2) the balanced valve stem is driven to move backward, and the high-pressure gas in the gas storage space is rushed into the homogeneous jet nozzle and shock tube to cause shock waves (Figure 4b,c); and (3) when it works again, the balanced valve stem is driven to move forward so that the inlet of the high-pressure storage tank is precisely between the front and rear sealed parts of the balanced valve stem, then high-pressure gases can be input again to prepare to generate shock waves (as shown in Figure 4a).  
Compared with current generators, the new shock wave generator has the following advantages: (1) low labor cost: there is no need to notch the metal partition and to disassemble screw locks and a large number of joint bolts, which is easy and can reduce the labor cost; (2) high operating efficiency: the shock wave generation process needs no manual intervention, which can reduce the experimental failure rate and improve the shock wave generation efficiency; (3) high safety: no foreign matter and debris are rushed into the shock tube with airflow, which can improve the safety of the operator and reduce the need for equipment maintenance; and (4) repeatability: after shock waves are generated, as long as the high-pressure storage tank is filled again, the generator can generate shock waves again. Hence, this generator enables supersonic shock wave generation experiments to be repeated dozens to hundreds of times each day and helps to design the automatic control architecture of the continuous shock wave generator, for example, the application in the power generation systems driven by supersonic shock waves.  
Figure 4: A schema presenting the working of the supersonic shock wave generator. (**a**) The gas storage space is filled with high-pressure gases to make the balanced valve stem static and balanced. (**b**) The balanced valve stem moves backward to allow gas circulation between the gas storage space and jet nozzle. (**c**) The high-pressure gases are rushed into the homogeneous jet nozzle and shock tube to generate shock waves.  
Figure 3: Structure of the new supersonic shock wave generator.