The Olympic torch adopts a brand-new intelligent induction ignition system and burner structure, and applies advanced electric pulse ignition mode, flameout prevention protection device and solenoid valve assembly to ensure that the torch is both wind-proof and rain-proof, so as to achieve the effect of "the wind stands in the rain and does not extinguish" and the torch relay is not disturbed by external environmental changes. The structural features and basic workflow of the torch for Beijing Olympic Games The core of the space flight is the combustion system of the torch for Beijing Olympic Games in 2008, which includes two parts: fuel supply system (fuel bottle, pressure stabilizing device and heat storage device) and burner. When working, the switch tool opens the normally closed switch valve on the fuel bottle clockwise. The high-pressure propane vapor in the bottle is depressurized by the pressure stabilizing device and maintained at a relatively stable pressure value, and then enters the regenerative copper tube through the side hole of the fuel distributor with five air holes, flows through the combustion chamber and the fuel bottle, re-enters the fuel distributor, and enters the precombustion chamber and the main combustion chamber from two paths for combustion respectively. The main components of the fuel supply system for fuel bottle are pressure stabilizing device and fuel bottle, which are independently developed by adopting domestic advanced technology and technology. The fuel bottle adopts seamless cold-drawing technology, with a diameter of 32 mm, that is, it is drawn into its present shape by a whole piece of plate, so it is very resistant to pressure (up to 14 MPa), which is equivalent to bearing the pressure above 1400 meters underwater. Due to the time requirement of torch burning, a bottle of fuel needs to burn for more than 15 minutes. Besides the torch shape, the burner also has certain flow requirements. Therefore, in order to ensure the matching with the torch shell and meet the burning time, the fuel bottle can only be made thin and long. This is technically more difficult. Because it is integrally formed, and the wall thickness of the fuel bottle wall is less than 1 mm, it is easy to crack when the slenderness ratio reaches 7.5 times. The choice of fuel is propane with purity over 99%. Historically, the Olympic torch has used more mixed fuel. Propane fuel is used to meet the environmental temperature requirements in the torch relay route. Secondly, color is also a consideration. After propane burns, the flame is orange and the visibility is good. The voltage stabilizing device is also specially developed. The pressure of the gas coming out of the fuel bottle is unstable and decreases with the decrease of temperature. The combustion of the torch needs a stable flow, and the function of the regulator is to provide fuel supply with a certain pressure and flow, which is the same as the principle of the general regulator. The gas fuel enters the inlet of the pressure stabilizing device at a higher pressure and flows out at a pressure higher than the ambient pressure in a certain range to ensure the fuel pressure and flow required for combustion. The design requirements of voltage regulators are usually small, light and multifunctional. The current voltage stabilizing device has four functions: first, the flashlight switch is designed on the voltage stabilizing device, and the voltage stabilizing device is missing a part; The second is decompression; The third is voltage stabilization; The fourth is to ensure that the torch continues to burn without danger in the event of accidental fall. Connection of fuel bottle and pressure stabilizing device The fuel bottle and pressure stabilizing device are connected by threads, and the fuel bottle mouth has external threads, and the pressure stabilizing device has internal threads. Although this is not original, it is rarely used in the torch. In the past, some torches used ready-made fuel bottles, and most of them used direct jacking. If the air pressure is too high, the thimble will be pushed tightly and it will be difficult to use. If the pressure is too small, it is easy to loosen due to vibration during use, resulting in air leakage; At the same time, due to inaccurate positioning and sealing, it is easy to leak due to lax sealing during compaction or use, which is neither safe nor easy to extinguish. We have learned the experience and lessons of foreign torches and adopted a threaded interface. Both the 2000 Sydney Olympic Games and the 2002 Salt Lake City Winter Olympics torches used heat preservation devices. Because for gas phase combustion, if there is no effective heat supplement, the temperature of the fuel bottle will drop. When the fuel is at low temperature, the steam pressure will decrease, which may affect the combustion performance of the torch. The original design encountered this problem. When it was first developed, the fuel bottle was bulky, so it cooled slowly. Now the fuel bottle is smaller, the burning time is longer, and the thermal device needs to be added back. To heat, there must be a heat source, so it is natural to use the flame heat of the torch itself-the fuel does not directly enter the combustion chamber after it comes out, but heats the fuel bottle through the heat storage system to slow down the cooling speed and meet the combustion time. Another advantage of the regenerative tube is that it is impossible to exchange all the heat through heat exchange, so the temperature of the gas in the tube is also increased, which is beneficial to combustion, which is an additional benefit. The burner is designed with double flames as the core, which is used for the first time in China. After heat storage, the fuel oil is divided into two paths, one of which enters the precombustion chamber and the other enters the main combustion chamber, and is basically distributed according to the ratio of 1:2. The center of the bottom of the precombustion chamber is a nozzle, and the periphery is an air inlet. There is also an air inlet channel with a certain area at the bottom of the torch shell. When the fuel in the precombustion chamber is injected upward, it will drive the surrounding air to rise and enter the precombustion chamber, which is the injection effect. The fuel and air in the precombustion chamber are mixed and then burned. Just like our gas stove, the flame is well mixed and burned fully. The flame has high temperature, short shape and blue color, which is not easy to see under strong light. However, the fuel in the main combustion chamber is not premixed, and it is mixed with air after being sprayed out, and then diffused and burned, and the flame temperature is slightly lower and it is opaque orange. The flame height is higher than 25 cm. The precombustion chamber is equivalent to a stable fire source, ensuring that it will never go out. Even if the flame of the outer main combustion chamber goes out, the main flame will be ignited immediately. There are similar designs of double flames abroad, but they are not the same, and they are not premixed. Like the 2006 Winter Olympics in Turin, there are also two combustion chambers, but both are diffusion flames. We consider using premixed flame, mainly because its temperature is higher and it is easier to reignite the main flame. On the other hand, the main flame is above and the pre-combustion flame is below, which is relatively less affected by the outside world and is easier to protect the flame. Our design is actually inspired by the air-breathing engine. Because some engines also have a small precombustion chamber. It should be said that this scheme is the first time in the use of the torch. It is also very special that the main flame is ejected from the uniform holes in the circular tube. Many foreign countries use small nozzles, or although there are multiple nozzles, the size is relatively large. We have also done experiments on this scheme. On the one hand, it is not conducive to the stability of the flame, on the other hand, it has a large smoke when burning. In our current design, the flame can be ejected from the small hole of a ring. One of the advantages is that the ejected fuel is relatively uniform and is a circular flame; The other is that the sprayed fuel can be mixed with air more evenly, and the smoke will be small when it is fully burned, which is beneficial to viewing and environmental protection. During the development of the torch, we found that the wind speed has the greatest influence on the torch's work, and a lot of experiments were carried out on special equipment to ensure that the torch will not stall under strong winds and small winds. We really hope to get a flashlight with reliable and stable performance. We believe that we should continue to evaluate the torch parameters in the actual environment in the future and ensure the development quality through strict production processes. We expect the Beijing Olympic torch to spread the same dream in the same world.