Design and calculation of industrial coolers

1、Design basis

Design Standard for Steel Structures GB50017-2017Steel Structure Design Manual, China Construction Industry Press, January 2004

Code for Construction and Acceptance of Steel Structures (GB50205-2020)

British Code for Design of Steel Structures (BS5950)

2、Design load

Load includes structural self weight, wind turbine constant load, live load, snow load, wind load, etc. The structural calculation adopts the ultimate stress method, therefore, the load value is larger than usual. The surface load is calculated based on the distribution coefficient and applied to the platform according to the line load. The wind load is calculated based on the wind vibration coefficient, body shape coefficient, and basic wind pressure to calculate the wind pressure values on four surfaces, which are then converted into line loads and applied to the columns. Auxiliary components such as stair handrails are applied to the stairs according to uniformly distributed loads.

1. Constant load

The self weight of the steel structure is automatically calculated by the program, and the node weight is considered based on the self weight of the structure multiplied by 1.3. The weight and fluid load of the radiator are applied by external forces.

Platform constant load: 0.50kN/m2

2. Live load

Live load of the platform for loading: 2.5kN/m2

3. Snow load

According to relevant design data, the snow pressure can be basically calculated as 0.4N/m2.

4. Wind load

Calculate according to the maximum value.

Basic wind pressure: 0.35kN/m2, height variation coefficient of 1.8, wind vibration coefficient: 1.5, ground roughness category: Class A

Class.

Is the standard value of wind load, is the wind vibration coefficient at height Z, is the shape coefficient of wind load, and is the coefficient of wind pressure height variation.

When the standard value of wind load is less than 0.75kpa, calculate based on 0.75 kPa and multiply by 1.4 times the safety factor. Namely

5. Temperature load

The temperature difference is relatively small. The structural form is single, and the linear expansion of steel has a relatively small impact on the overall performance of the structure, which can be ignored.

6 Earthquake loads

According to the seismic analysis design method: small earthquakes do not damage, medium earthquakes are repairable, and large earthquakes do not collapse. Small earthquake analysis can be divided into: bottom shear force method, response spectrum analysis, and elastic time history analysis. Medium earthquake analysis is calculated by multiplying small earthquake analysis by amplification factor.

Seismic fortification intensity: 8 degrees

Design basic seismic acceleration peak value: 0.3g

Construction site category: II site

Design grouping: Second group

Damping ratio: 0.05

This structure adopts MIADS software for overall modeling and analysis. During modeling, beam elements are mainly used for each structure. In order to facilitate loading, plate elements are established at the structural platform. Consolidation is used as the boundary condition at the bottom of each column, and constraints are applied at the connection between the column and the original structure according to the actual situation. The structure includes upright column, cross brace, slant support and upper and lower platform steel structure.

Load sub factors and load combinations:

3、 Radiator calculation

1. Material parameters

Aluminum alloy adopts 6005-T1, with tensile strength and yield strength equivalent to 6063-T5, tensile strength ≥ 150Mpa, yield stress ≥ 110 Mpa. According to the performance table of aluminum alloy, it is found that 6063-T5 has a tensile strength of 185Mpa, yield stress of 145 Mpa, and fatigue strength of 90MPa.

2. Working condition analysis

The calculation of radiators can be divided into 1. lifting ondition,

3. operating condition (operating condition is divided into

4.support and lifting point participate in force simultaneously.

5.support bears gravity, while lifting point bears horizontal force.

6.support does not bear any force, that is, when the overall structure is subjected to uneven settlement, there is a suspension at the bottom)

To ensure its stability, it is recommended that the foundation treatment should be pre compressed and settlement assessment should be carried out during the overall installation.

2.1 Hoisting conditions

At this point, the radiator is only considered for its own weight due to the lack of fluid injection, and is lifted and installed through a side lifting point. Because no other accessories were installed during modeling, in order to estimate the weight more accurately, its self weight coefficient was defined as 1.3.

The radiator structure consists of 1, frame 2, support beam 3, heat exchange tube 4, tube plate, and other ancillary structures. As the heat exchange tube and support beam are fixed together through a corrugated plate, it can be considered that the heat exchange tube participates in the structural stress, which leads to strain and stress generation.

The overall structural model is

Radiator structural model

The overall deformation of the radiator during the lifting process

Stress cloud diagram of radiator during lifting process

From its displacement cloud map, it can be seen that its overall deformation is 1.2mm, and the maximum stress is 15MPa

Stress cloud map of heat sink

Displacement cloud map of heat sink

From its displacement cloud map, it can be seen that its overall deformation is 1mm and the maximum stress is 2MPa. Through calculation, it can be seen that horizontal lifting has little effect on the heat dissipation fins, and its deformation and stress are far less than the standard requirements.

The vertical lifting situation is as follows:

Vertical lifting stress cloud map