The Beijing Winter Olympics are in full swing, and the artificial snowmaking technology behind it has also become the focus of the Olympic Games, and just 5 years ago, the mainland's artificial snowmaking technology was neither advanced nor mature, and was firmly blocked by the United States, Japan, Britain and other countries. Some ski resorts have to spend huge sums of money to import a high-end snow machine, and have signed a series of complex agreements, and there are also high maintenance fees when the equipment fails.
More importantly, the winter snow resources of Beijing, Zhangjiakou and Yanqing, which are the winter Olympic areas, are not abundant, and it is difficult to see several snowfalls throughout the winter under extreme circumstances, so artificial snowmaking has become a must. In fact, as early as 2015, the International Olympic Committee pointed out that the three competition areas on the mainland need to be equipped with stable artificial snowmaking facilities, and some venues in Zhangjiakou and Beijing even rely on artificial snowmaking.
Of course, the implementation of artificial snowmaking has almost become the "standard" of the host country in recent years. 2014 was a typical warm winter, and it was in this year that the Russian Winter Olympics were held. According to Russia's plan, the 500,000 cubic meters of storage were enough to ensure the smooth progress of the race, but some of the runways that encountered high temperatures could not meet the requirements, so they had to quickly allocate 450 snow machines to solve the urgent need.
A new type of snow machine was developed
The principle of artificial construction is not complicated, generally cold water is frozen first, and then the ice is chopped and mixed with air and sprayed. The specific method is to mix the compressed air and cold water below 5 ° C and press it into the -25 ° C evaporator together, the cold water meets the cold and freezes, and then the cutting machine will shred the ice cubes that have become a specific shape, along with the high-speed attack of the air, these fine fog particles encounter outdoor cold air and quickly condense into Xiaoice crystals, that is, common snowflakes.
In 1950, American Wayne Pierce connected the hose and nozzle for flowering to a paint spray compressor and made the world's first snow machine. Although the snow making efficiency and snowflake quality of the snow machine are getting higher and higher, the principle has not changed.
If this is the case, why has the mainland not been able to conquer snowmaking technology for a long time? What is the difficulty?
Effectively controlling the size of snowflakes is undoubtedly the biggest difficulty in snowmaking technology. If the snowflakes spewed out by the snow machine are too large, the snowflakes will fall to the ground in a very short time, and even form a layer of thick snow after the cold, and the ground immediately becomes "adversity" after the contestants slip one by one; if the snowflakes are too small, they will be much softer than the natural snowflakes, and the players may fall into it after sliding, and even cause personnel injuries.
This requires that the fine fog particles spewed out by the snowmaker should not be too large or too small, and a large number of experiments and measurements need to be carried out in a low temperature environment. The technical problem of artificial snowmaking is That Wang Feiteng and Academician Qin Dahe and his team have successfully developed a snow machine at the world's leading level after thorough research and repeated experiments.
The traditional snow machine cuts frozen ice into sheets of ice that are 5 mm long and about 1 to 1.5 mm thick, and then sprayed by air. The new snowmaker on the mainland uses high-pressure air to first strike the water flow into fine fog-like particles and be sprayed out. The mist particles meet the outdoor low temperature cold air and condense into snowflakes. The new snow machine can generate 9 different types of snowflakes, with a minimum size of 0.3 mm and a maximum of 10 mm, of which 0.3 mm of snow can be paved into a natural state of the snow.
The new snow machine seems to have a simpler structure. In fact, because the outdoor temperature is high and low, the speed of forming snowflakes is large and small, and the volume is uneven, so this requires adjusting the temperature and spray speed of high-pressure air at all times. Of course, this task has been entrusted to the built-in chip to adjust the cold air temperature according to the outdoor temperature.
It is understood that there are hundreds of new snow machines, and the Winter Olympics will produce 105,000 cubic meters of snow and 125,000 square meters of snow, which has played an important role in the smooth progress of the Winter Olympics.
Snow that never melts
Just when the mainland broke through artificial snowmaking technology and broke through the blockade of foreign technology, mainland scientists made new contributions and successfully developed "snow that does not melt."
"Science and Technology Winter Olympics" theme exhibition appeared a special snow, the snow named gel ice and snow, developed by the team of Zhang Kai, a professor at the School of Astronautics of Beijing Institute of Technology, its magic is that it has the characteristics of snow but does not melt, and there is a cool and slippery feeling after touching the hand.
Gel ice and snow, as the name suggests, is a gel with a moisture content of more than 90%, and the texture is similar to that of jelly at room temperature, but the mechanical shape is better. When a heavy object is pressed on the surface of the gel, a deep pit is pressed out, but after the heavy object is removed, it can be recovered immediately, and it can be rolled up like a blanket for collection.
Gel ice and snow do not melt because it is composed of a network of hydrophilic polymers, formed by polymerization reactions that are chemically implemented on a variety of materials. Experiments have found that when there is no polymer network, the attached ice crystals will melt into water as soon as the temperature rises; when there is a polymer network blessing, the water melted by the ice crystals after the temperature rises will still be firmly bound by the network. That is to say, the gel is a substance between solid and liquid, and the common antipyretic patch and mask are a kind of hydrogel.
The material for producing gels is non-toxic and harmless, and has broad application prospects. In some small cities of the fourth and fifth lines, if the use of snow machines to do "ice and snow city", is undoubtedly a huge investment, the operator will most likely lose a bottom, but the use of gel ice and snow to form a layer of ice board, coupled with refrigeration units can quickly become a small ice rink, the only big expenditure is the electricity bill.
In addition, the ice and snow gel can also be used with the refrigeration unit to make ice sculptures and reliefs, even if someone touches it, there is no need to worry about damage. In the ice and snow-themed café, ice and snow gel can also be used to make ice bowls and ice cups, because they do not melt, do not deform, and have enough toughness to use for a long time.
Original: Blog post