The latest issue of the CAD/CAM/CAE Observer magazine No. 2 (150) / 2022 published an article by Sergey Bryuzgin, Head of the Department of Design of Heating, Ventilation, Air Conditioning, Smoke Protection and CFD Modeling at Metropolis, on the use of CFD modeling in the preparation and analysis of design solutions. The material was prepared together with the Sarov Engineering Center.
CFD modeling or Computational Fluid Dynamics is a branch of continuum mechanics that uses numerical methods to simulate the movement of liquids and gases.
Prerequisites for the development of mathematical modeling in the construction industry
The main prerequisites for the introduction of mathematical modeling in the design work of our company were the following factors:
- the complexity of designing modern buildings with distinctive sophisticated spaces (for example, atriums), for which it is not possible to confirm the microclimate parameters using standard methods;
- the need to design cultural and sports facilities, the premises of which require the maintenance of specified microclimate parameters (museum halls, exhibit storages, ice arenas, swimming pools, water parks, etc.);
- the presence of complex non-standard nodes that need to be checked from the point of view of freezing as part of the design of complex architectural forms;
- the need for a preliminary assessment of design solutions to identify possible problems at an early stage of design;
- the need to conduct an examination of design solutions with the choice of the optimal engineering solution.
Requirements for modern buildings
For the successful implementation of projects (including from a commercial point of view), it is currently necessary to take into account the following basic requirements:
- high aesthetic requirements for the building;
- minimization of energy consumption;
- maximum comfort for the end user;
- healthy atmosphere in the building;
- security of the building;
- minimization of construction time;
- minimization of construction cost;
- digitalization of the building (obtaining digital twins of buildings).
After analyzing modern design trends and requirements, our company decided to implement mathematical modeling methods in its projects.
Choosing a software package and a supplier
At the first stage, it was necessary to choose a software package for performing calculations. After conducting a comprehensive analysis of the market for specialized software, as well as the companies providing technical support and training, we opted for the Siemens Star CCM+ package with the purchase and subsequent support from the SAEC (Sarov Engineering Center).
To test and verify the technology, a non-commercial project was used - a water park in the city of Mytishchi. Microclimate measurements were taken at the facility, after which we conducted their modeling together with the SAEC engineers. On this model, we worked out the methodology and verified the mathematical model.
The results turned out to be very close, the discrepancy was about 10%, which, in our opinion, is a very good indicator.
The problem of introducing computer modeling tools in the construction industry
At the stage of implementation of mathematical modeling tools, our company faced the following difficulties:
- significant initial financial investment;
- lack of trained personnel;
- tight deadlines for mathematical modeling during design.
Initial financial investment
The first difficulty is the high cost of the software package and server hardware. The acquisition of complex high-tech software, as well as the corresponding equipment, is an expensive pleasure.
In order to optimize costs, it was decided to break the implementation into two stages.
The first stage is the acquisition of a small, relatively inexpensive license. Such a license does not require high-performance hardware, so a normal computer with good technical characteristics is suitable for work. At this stage, we could solve current - relatively simple - project tasks, as well as train employees to work with the software.
The second stage is the purchase of a full license and a productive workstation, as well as the formation of a division for mathematical modeling.
Lack of trained personnel
At the initial stage of development of this direction in the construction industry, there were practically no specialists involved in mathematical modeling. We solved this problem by training the company's employees by creating an internal educational course.
In the future, we plan to expand this competence within the company, and we also want to take on an educational mission and train university students who have an internship in our company.
Terms of performance of works on mathematical modeling
One of the main criteria for the successful application of mathematical modeling methods is the rapid adoption of the correct and most rational design decision. At the same time, the accuracy of the initial geometry of the model directly affects the accuracy of the result.
The construction area is characterized by the fact that the final exact geometry of the calculated regions can only be obtained at the final stage of the project; if the decisions made were not optimal, then the changes made can roll back all project participants far back. In order to make changes to the project on time, our project team made it a priority to develop methodologies that allow making and verifying design decisions already at the initial stages of design. This allows us to get good results without delaying the design process and minimize design changes.
Development of the HVAC department
In terms of organization, it was decided to create a small department for mathematical modeling, consisting of engineers from the Heating, Ventilation and Air Conditioning (HVAC) department. These specialists had extensive knowledge in the construction field (heat engineering, microclimate, etc.), which allowed them to quickly master the capabilities of the software package and begin to perform mathematical modeling tasks.
Within the framework of the HVAC department, the specialists of our company successfully solve the problems of calculating:
- thermal conductivity of complex three-dimensional nodes;
- external aerodynamics of buildings;
- aerodynamics of non-standard elements of ventilation systems;
- air distribution from non-standard air distributors and optimization of their design;
- indoor microclimate parameters, as well as optimization of design solutions.
It should be noted that our company is actively working in the BIM environment using the Revit software package from Autodesk. Data from Revit is well imported into the Siemens Star CCM+ environment, which allows you to quickly get the calculated geometry, as well as quickly modify the data to achieve the optimal result.
Performing engineering analysis has a positive effect on the quality of projects, ensuring the validity of design decisions and reducing project risks. Moreover, customers receive optimal, guaranteed working solutions. Projects become balanced.
An example is the project of reconstruction and redevelopment of the GES-2 House of Culture, within the framework of which CFD modeling of complex three-dimensional nodes was carried out.
Solving large-scale problems together with the SAEC company
Quite often there is a need to solve large-scale problems in a short time. To do this, together with the SAEC engineers, we have developed a flexible approach that allows us to optimize resources by performing part of the work in parallel and using joint server capacities.
Work on the preparation of the initial geometry and data for setting the boundary conditions is carried out by the specialists of our company. Then all the data is transferred to the SAEC company, where the engineers check our decisions and adapt the data for numerical calculations. After several short discussions in a short time, we get a proven design solution, on the basis of which the SAEC engineers perform numerical simulations. As the calculation progresses, we also hold short joint meetings and, if necessary, make changes to the initial data. This approach allows you to quickly adjust the project and get a good final result without violating the design time.
Together with the specialists of the SAEC company, we have completed quite a lot of projects, as a result of which we were able to develop optimal conditions for interaction.
Among these projects are:
– The ice arena of the Dynamo stadium named after Lev Yashin – CFD modeling of the microclimate of the ice arena was carried out.
– The Rhythmic Gymnastics Palace of Irina Viner-Usmanova – CFD modeling of the main arena and training halls. The main requirement was to ensure a comfortable microclimate and minimal air movement during the performances of gymnasts with a gymnastic ribbon.
– Atrium in high-rise buildings of class “A” iCITY multifunctional complex. CFD modeling of the atrium microclimate was carried out taking into account the stack-effect (traction effect that occurs in buildings during the cold season due to the temperature difference inside and outside, when the connected volumes are elevator shafts, stair cells, etc. - begin to work like a pipe). It was necessary to confirm the comfort of the microclimate in the atrium.
Expansion of the scope of mathematical modeling services
Initially, we used mathematical modeling methods for our internal purposes, since they allowed:
- identify problems at an early stage and optimize design solutions in time;
- reduce the time spent on substantiating design decisions - in the examination bodies and for the customers;
- reduce project risks by verifying solutions on the digital twin of the facility;
- speed up project launch;
- make the living environment for the people in the building as comfortable as possible;
- reduce customer costs during construction and operation.
With the introduction of mathematical modeling methods, we have seen an increase in customer interest in these services. If three years ago we received about one or two large projects a year, now the demand has increased several times. Therefore, we decided to separate the services of mathematical modeling into an independent direction.
Our plans for the future:
- detachment of CFD modeling into a separate structural unit;
- expanding the competencies of company employees;
- expanding the list of work performed;
- increase in the scale of work performed;
- increasing the attractiveness of design solutions for the Customer;
- time optimization at the stages of project execution and CFD modeling.
Read the full material in the digital issue of the magazine.