Large-scale low-temperature controllable atmospheric boundary layer test system for wind and snow simulation
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Solution Overview
Problem
Current wind tunnels are inadequate for simulating the atmospheric boundary layer environment around large-scale structures, such as buildings, due to their small cross-sectional size and significant wall effect, which prevents the testing of three-dimensional building models and research on wind-induced snow drift on large-span spatial structures.
Innovation Solution
A large-scale low-temperature controllable atmospheric boundary layer test system comprising an atmospheric boundary layer wind tunnel, a plenum chamber, and a refrigeration system, where the plenum chamber is integrated within the wind tunnel to simulate snowfall and maintain a low-temperature environment, allowing for the reproduction of realistic wind and snow conditions on large-span structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If existing wind tunnels are used for snow simulation, then small-scale objects such as vehicles can be tested, but large-scale structures such as buildings cannot be tested due to small cross-sectional size and significant wall effect
Solution Approach 1:
The wind tunnel test section is divided into multiple independent cold rooms that can be combined. Each cold room has its own insulation and temperature control, allowing the test section to be segmented for manufacturing and assembly while maintaining overall performance. This segmentation enables construction of a larger test section that reduces wall effects on full-scale building models.
Solution Approach 2:
Multiple cold rooms are nested within the wind tunnel structure, with each cold room containing insulation layers and cooling systems. The cold rooms are arranged to form the test section, with snow storage and distribution systems nested within the plenum chamber above the test section. This nested arrangement maximizes the use of space while maintaining thermal isolation and enabling large test section dimensions.
2Adaptability or versatility
If existing wind tunnels are used for snow simulation, then simple wind flow can be generated, but realistic wind-snow coupling environment cannot be created
Solution Approach 1:
The wind tunnel system is designed to perform multiple functions: generating controlled wind flow, maintaining low-temperature environment, storing and distributing snow particles, and simulating atmospheric boundary layer conditions. The plenum chamber serves multiple purposes as both snow storage and snow distribution mechanism. This multi-functionality allows realistic wind-snow coupling environment simulation while managing system complexity through integrated design.
Solution Approach 2:
A plenum chamber is introduced as an intermediary component between the snow storage system and the test section. The plenum chamber receives snow particles and distributes them uniformly across the test section, mediating the interaction between the snow supply system and the wind-snow environment. This intermediary enables controlled snow particle introduction without directly complicating the wind flow generation system.
3Reliability
If large-span spatial structures are tested, then realistic building conditions can be simulated, but testing becomes impossible due to blocking rate limitations in existing wind tunnels
Solution Approach 1:
The wind tunnel is designed with a large cross-sectional area to accommodate full-scale or scaled three-dimensional building models. By increasing the horizontal dimensions of the test section, the blocking rate (ratio of model cross-section to tunnel cross-section) is reduced, allowing realistic simulation of large-span spatial structures without significant wall effects or flow interference.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively simulates the accumulation and evolution of snow on large-span spatial structures under wind-snow coupling effects, providing a high-quality test platform for determining roof snow loads and addressing the limitations of existing wind tunnel technologies.
Implementation Method 1
a refrigeration system, wherein the refrigeration system outputs a secondary refrigerant for heat exchange for the air cooler in the plenum chamber and the air heat exchanger in the settling chamber of the atmospheric boundary layer wind tunnel
Implementation Method 2
the refrigeration system outputs a secondary refrigerant for heat exchange for the air cooler in the plenum chamber and the air heat exchanger in the settling chamber
Data Source
AI summary
The present disclosure provides a large-scale low-temperature controllable atmospheric boundary layer test system and method for wind and snow simulation. The system includes an atmospheric boundary layer wind tunnel, a plenum chamber and a refrigeration system. The atmospheric boundary layer wind tunnel includes an upper flow channel and a lower flow channel communicating with each other end to end. A power section is arranged in the upper flow channel. A settling chamber, a contraction section and a test section are sequentially arranged in the lower flow channel. Corners of a closed return wind tunnel are respectively provided with a transition section. A fan is disposed in the power section. An air heat exchanger is disposed in the settling chamber. The plenum chamber is divided by a partition into a storage room for storing snow particles and an operation room provided with a snow particle vibratory spreading device. The storage room is located at an upper part of the settling chamber. An air cooler is disposed in the storage room. The operation room is located at an upper part of the test section. The snow particle vibratory spreading device spreads snow particles that uniformly fall into the test section. The refrigeration system outputs a secondary refrigerant for heat exchange for the air cooler in the plenum chamber and the air heat exchanger in the atmospheric boundary layer wind tunnel. According to the present disclosure, the natural snowfall process is simulated through the cooperation of various parts of the system.