The Winter Olympics were born in 1924 and have gone through 98 years, from the original Chamonix in France to the current Beijing-Zhangjiakou, from skiing, skating, ice hockey and luge to today's 15 major events and 102 minor events. The number of participating countries in the Winter Olympic Games is increasing day by day, the addition of new projects is mushrooming, and the connotation of the Winter Olympic Games is constantly enriched on the basis of peace, friendship, unity and care. Behind such an ice and snow feast, there is people's obsession with winter sports competitions, there is also a precise and orderly preparation between various departments, and there is a great help from modern science and technology, with the perfect end of the Beijing-Zhangjiakou Winter Olympics, we will review the key link of the Winter Olympics - snowmaking technology.
To run a world-renowned ice and snow feast, strong infrastructure support is indispensable, and its core is snowmaking technology. The quality of snow has an important impact on the performance and performance of athletes, unlike the outdoor ski resorts for daily entertainment, the snow used in the event has extremely high requirements for quality, not to mention the snow used in the Winter Olympic games, in terms of snow density, the density of new snow is 150 ~ 200 (kg / m3), and the snow density accumulated by the snow groomer is only 300 ~ 350 (kg / m3), but the World Cup and higher event tracks require snow density of 540 ~ 560 ( kg / m3), and the snowmaking difficulty is full.
In addition to the snow density, there are other strict requirements for the Olympic Games with snow, below we look at a map of artificial snowmaking meteorological conditions in the Swiss mountain ski field in the United States, it doesn't matter if you don't understand it, the purpose is to let everyone experience only two parameters can bring about the "dazzling", remind you, this is the snowmaking meteorological conditions that can be required in outdoor conditions Oh, for the changeable winter weather, it is simply harsh to make people headaches!
Taking the ancient poplar stadium group of this Winter Olympics as an example, the snowmaking layer of the landing slope has three layers: the base, the middle and the surface, and the density requirements of each level are different, the thickness requirements of different areas are also different, and the difficulty of snowmaking can also be seen. Now the ancient poplar stadium all the "snow types" have a total of nine kinds, and can also be made according to different needs of different types of snow, fine snowmaking to meet the diversified and high-quality needs, can be called the gospel of obsessive-compulsive disorder patients, let us praise the scientists!
1
How are snowflakes formed?
In nature, most snowflakes are at low temperatures, the water vapor in the air condenses into small droplets in the supersaturated state, and is enriched on the surface of the condensation nucleus, crystallizing to form a small crystal nucleus, and the small crystal nuclei continue to adsorb the surrounding water vapor and grow continuously, eventually forming a complete snowflake. Therefore, the formation of snowflakes must meet three conditions: one is that the water vapor in the air reaches a saturated state, and the relative humidity is greater than or equal to 100%; the second is that there must be condensation nuclei in the air, that is, tiny solid particles suspended in the air that are easy to absorb water; the third is to maintain the temperature and humidity of the ice and snow retention structure.
The shape of snow crystals is diverse, the main shapes are plate-like, prismatic, branch-like, needle-like, and the shape of snow crystals formed at different temperatures is also different, and the shape of snow crystals will also change with temperature. In the low temperature environment, as the water vapor continues to condense on the snow crystals, the snow crystals of different shapes slowly grow and develop, with the further condensation and aggregation of water vapor, directional migration, the snow crystals merge with each other, and the accumulation of snow crystals appears, and our common hexagonal snowflakes are slowly formed in this process, as if the cultivation game developed by the sister of the young girl has Yuki You (green girl - the god of frost and snow in ancient Chinese mythology and legend).
There are no two snowflakes in the world that are exactly the same, although the "talent point" of each snowflake is strangely pointed by the sister of the young girl, but the basic form of the snowflake is a hexagonal plate and columnar, which is closely related to the characteristics of water vapor crystallization, first of all, water vapor gathers around a condensation nucleus and forms a small droplet.
Subsequently, the water vapor will gradually form a hexagonal crystal nucleus when crystallizing, because the six edges and corners of the crystal nucleus adsorb water vapor and crystallization speed is the fastest, so its growth rate is also the fastest, immediately formed six main crystal branches, and it is these six crystal branches that lay the foundation for the hexagonal snowflake structure, and the position on the crystal surface is relatively slow, so a concave area is formed, forming a gap between the snowflake crystal branches, naked discrimination!
But careful friends can find that just like the main branches of trees grow fine branches, snowflakes not only have six main branches, but also have a variety of side branches on the main branches, which is due to the chemical bonds formed by water when crystallizing, as well as the change of temperature and humidity in the air, etc. Under the combined action of snow crystals melting, crystals constantly changing their form and continuing to grow.
As early as 1930, scientists summarized 21 types of snowflakes, and by 2013, the number reached 121. However, other types of snowflake forms are also mostly the development, metamorphosis or combination of the two basic forms of hexagonal plate and columnar, and when the buoyancy of the air cannot carry the weight of the snowflake, it will form a natural snowfall.
Olympic Winter Games
2
Development of snow machines
The principle of artificial snowmaking is roughly the same as the formation of snow in nature. In 1950, Americans Wayne Pierce, Art Hunt and Dave Richey invented the world's first snow machine, which was also the prototype of the later snow gun (it is also seriously suspected to be the prototype of the Frost Mushroom in Plants vs. Zombies). The principle of the first generation of snow machine and the current use of handheld pressurized watering can is similar, in cold conditions, the use of compressed air to spray water in the air to implement artificial snowmaking, you small friends when you were young must have the summer with the watering can against the sun to create a rainbow experience, imagine now spewing out the snow of bling bling!
In 1958, Alden Hanson invented a new type of snowmaker, the Fan Snowmaker, which was more mature than the first generation of compressed air snowmakers and used tiny dirt particles as condensation nuclei. In 1969, Erikson, Wollin, and Zaunier of Columbia University optimized the structure of the fan snowmaker, improving the efficiency of snowmaking, and because the fan snowmaker structure was simpler, requiring only electricity and water, it was later widely used in various snowmaking scenes.
Nowadays, the masters of the artificial snow-making sect, such as the internal mixed snow machine, the outer mixed snow machine, the fan type snow machine, and the ice crusher snow machine, their kung fu is also inherited from these two old predecessors, and they have developed their own practices, but in the end, there are two cultivation outlines, the first step, the deep internal cultivation behavior - to create a suitable low temperature snow making temperature. The second step, the ingenious luck trick - through the snow machine nozzle to spray atomized droplets, so that it freezes in the cold air around, forming the core component of the snowflake "crystal nucleus", and the crystal core then uses the "star-absorbing method" to use the surrounding atomized water vapor to turn it into its own use, forming a hexagonal snow crystal, and on this basis continues to adsorb the droplets to form snowflakes.
Although, it sounds that the cultivation of the Internal Gong Mind Method is rough and concise, but the combination of frost power and star-sucking Dafa with one body, it is by no means as simple as falling off a cliff and picking up the Inner Gong Mind Method in the cave, for details, see the figure below, let me do the Star-Absorbing Dafa to BoZuo Cold Zen Cold Ice True Qi (according to an unknown theorem, since ancient times to the left of the wave), and to integrate the lifelong martial arts of the two old fritters who have been mixed in the rivers and lakes for many years, it can be seen how difficult it is.
At the end of the 1960s and 1970s, Europe and the United States first in the snow machine manufacturing technology force, due to the high effectiveness of the mixed snow machine, the snow making effect is good, quickly occupied the mainstream market of the snow machine, in addition, Europe and the United States also took the lead in mastering many exclusive methods of internal power practice, in the past thirty years, the application for patents for artificial snow machines to Europe, the United States, Japan, South Korea, Europe and the United States snowmaking technology is ahead of Japan and South Korea, at the highest level in the world, not only in the mechanical structure of the snow machine has a large number of patents, but also in the automation technology, Intelligent control and energy saving are also far ahead of Japan, South Korea and mainland China, and have taken the lead in using more advanced predictive control algorithms, under the blessing of many technologies, Europe and the United States firmly grasp the position of the snow forest alliance.
Built-in artificial snow machine infrastructure
The mainland's ice and snow sports and industry started late, coupled with the technical blockade, the snowmaking industry chain is not complete, there is still a certain gap with the international advanced technology in the snowmaking machine manufacturing technology such as nozzles, nuclear devices, automation control, snow machine systems, etc., but with the vigorous promotion of the country and the efforts of the mainland's scientific researchers, the mainland's advanced snowmaking equipment will be a blockbuster, shining debut!
In addition, the concept of green and simple has always led the work of the Beijing Winter Olympics, Zhangbei flexible DC power grid project was completed and put into operation, providing 100% green power for the Beijing Winter Olympics (The Beijing Winter Olympics is the first in history, 100% use of green clean energy in the Winter Olympics, Zhangbei Soft Straight Project using the mainland's original, world-leading flexible DC power grid new technology, creating 12 world firsts, bursting praise! ）。
In terms of snowmaking water, the Beijing Winter Olympic Organizing Committee also pays attention to ecological security and the impact of regional life, the water resources required for snowmaking in Yanqing Racing Area are jointly coordinated by the reservoir, and the tap water required for life and ice-making water supply is supplied by the centralized water supply plant under the dam of Foyukou Reservoir, which not only effectively reduces the amount of groundwater exploitation in Chongli District, but also the residents' domestic water will not be affected by snowmaking.
The ski resort improves the carrying capacity of the water resources and water environment in the competition area by formulating measures such as water supply safety guarantee, sewage treatment, and water conservation in the competition area, and gives priority to the use of natural precipitation and surface runoff collected and stored as artificial snowmaking water sources. The artificial snowmaking system adopts the world's most advanced high-efficiency water-saving artificial snowmaking equipment and intelligent snowmaking system, which can dynamically maintain the best snowmaking efficiency and save water according to the external environment. Through real-time monitoring of meteorological conditions, choose to start the snow machine under the most suitable conditions to avoid snowmaking and waste of water resources. Truly carved green environmental protection on every cornerstone of the Winter Olympics!
Finally, let's bid farewell to the Winter Olympics and welcome the Winter Paralympic Games in March!
Resources
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. 2021-11-15(009)
■ Author: Bian Zhou
■ Editor: Liu Yuling
The reproduced content represents the views of the author only
Does not represent the position of the Institute of Physics, Chinese Academy of Sciences
Source: Stone Science Studio
Original title: Winter Olympics: I just want to make a snow, why is it so difficult?
Edit: Herding fish