Vadim Kalle, Step Logic: CFD modeling – logical continuation of BIM

Vadim Kalle: At the end of 2017 we made the decision to expand competences in the direction of design of the engineering systems due to use of technology of computational modeling of thermodynamic processes (Computational Fluid Dynamics modeling, CFD) based on software of Autodesk of CFD. In my opinion, CFD is natural and obligatory continuation of BIM design.

The BIM model contains information on the building, at least – about its architecture and the engineering systems. Further this model is transferred to the application of Autodesk of CFD which "reads out" geometry of premises and after a task of all boundary and initial conditions calculates three-dimensional fields of distribution of temperatures, speeds, pressure and a set of other physical parameters. At data definition of characteristics by an empirical method very approximate calculation turns out, and its practical value tends to zero.

Actually CFD is virtual testing laboratory where it is possible to check all critical, high-responsible engineering systems even prior to design engineering. Calculation in CFD is a guarantee of operability of a system. At a sketch stage we can already create configuration of the premises, for example, to place conditioners and racks with the IT equipment if we speak about DPC, and at the exit to show that a system will function even at the critical modes, overheating is excluded. Earlier we had to explain the calculations to customers "on fingers", to tell about relevant experience and the number of the implemented projects. But with transition of our company to CFD this process became much easier and is more transparent: when there is an object 3D model, vertical and horizontal sections from CFD, exact calculations of high-speed fields is a clear proof of the fact that a system will work.

Vadim Kalle: CFD is an integral part of modeling of technology difficult objects with big heat production. It is about DPC, server premises and also about buildings with a complex geometry which require exact calculation of distribution of air flows: laboratories, cinema halls, sports arenas, etc.

Visualization of calculation in CFD

For similar objects confirmation of the made project decisions is possible or empirical calculations which do not reflect a real picture and are average, or by natural modeling taking into account scaling ratios. If to speak about aerodynamics of buildings, then natural modeling – though a difficult method, but applicable.

And here for DPC it is necessary to construct full-scale model 1:1 in test laboratory with all nuances of architecture, distribution of capacities by racks, to install conditioners, to carry out measurements, to process data, to optimize the solution and further to repeat all tests. So for DPC the method of natural modeling cannot be reasonable economically therefore computational mathematical modeling – the only option for such objects: it allows to consider all their features and restrictions, to count at once several options, to visually compare and select optimal.

Surprisingly, but in our country only units are engaged in modeling of server premises and data centers using BIM+CFD technologies. Tsodostroyeniye is the difficult direction where there is a set of nuances, and we have considerable practices on it. At the same time many organizations "are ground" on residential construction: there are examples when CFD modeling of areas for the purpose of calculation of aerodynamic characteristics is made.

Vadim Kalle: CFD modeling can be applied to the solution of a broad spectrum of tasks. For example, if we speak about data centers, then thanks to this technology there is an opportunity to optimize a conditioning system and to reduce expenses on power supply. In buildings with an atrium part and the big area of glazing of CFD will help to increase efficiency of the climatic systems and to reduce energy consumption.

Besides, CFD modeling allows to calculate temperature fields not only in premises, but also in structural materials and also to simulate a wind load on them. These parameters are extremely important for strength calculations of the bearing building constructions, buildings and constructions, platforms, billboards, etc. Also accounting of a wind load allows to calculate more precisely the systems of natural ventilation and a heating system of buildings.

Vadim Kalle: Modeling and simulation of heatphysical processes for the large logistic center became one of the first projects. In BIM we designed engineering infrastructure of DPC, a warehouse complex and the buildings adjoining to it and also simulated buildings on the available documentation from architects.

Among the engineering systems there were a conditioning and ventilation, networks of power supply, SCS, video surveillance systems and security, gas fire extinguishing.

General view of server

Providing the correct temperature condition in DPC, its simulation at real project loading and the choice of an optimal configuration of partitions for separation of "cold" and "hot" corridors, settings of grids of a raised floor became an important problem which we solved using CFD.

Results of CFD modeling of server

In the summer of 2018 the whole world with tension monitored matches on fields of the FIFA World Cup 2018 in Russia. On the platform of the Festival of fans of FIFA on Sparrow Hills (Moscow) of Step Logic unrolled Wi-fi network. Prior to implementation of a system the decision to simulate as the access points located in boxes of an outdoor installation in the presence of solar radiation without forced ventilation will work was made. The calculation received in CFD showed that during the operation of the equipment overheating will be with the probability of 100%. Construction was as a result optimized, the corresponding coolers and ventilating grates are picked up, and a system fulfilled without failures during all festival.

Design model of a cabinet with access point

Results of CFD modeling of a cabinet

For one of the Russian innovation centers we executed modeling server with high density solutions. About 35 kW of power consumption are the share of one rack of DPC of the customer - it is almost superdense solution, further there are already supercomputers. We developed BIM model of the building and all engineering systems in premises, placed in machine halls of a rack with the IT equipment, interline conditioners, isolation of corridors. Calculation of CFD showed that the scheme offered by us will work: even at rotation of conditioners overheating is excluded.

General view of the building and server

One more interesting project – modeling of an air and thermal veil of an aviation hangar with sizes of aperture of 58 meters in width and 11 meters in height. In CFD the flowing part of canals which give air from below up in an aperture of gate was simulated, and the optimal solution for the correct distribution of air flows is selected. Further a constructive part, fans and all supplies were picked up. Naturally, it would be impossible to perform similar calculations with an accuracy required for implementation in the empirical way.

General view of an aviation hangar

Results of CFD modeling of a hangar

It would be desirable to pay special attention to the projects connected with conditioning of premises of the UPS. All usually forget that the UPS is cooled not as racks with IT, other expenses of air and temperature difference there at all. In case of overheating battery modules considerably lose the capacity. In one of premises of the known television center UPSes with a total power of 2.5 MW with considerable heat release are installed. The premises are long, narrow and, in terms of conditioning, difficult. We made BIM-and CFD models of an object and received real distribution of temperature of speeds indoors, defined a stagnant zone and issued recommendations about improvement of a conditioning system.

Vadim Kalle: In my opinion, the interesting direction of development of BIM is modeling of architecture of premises for adjacent sections. For example, for one large production holding we created BIM model of the whole plant with the large equipment which specialists of the customer "shifted" in the program for radio positioning modeling. Actually they reproduced reflection of radio waves from walls and constructions, and all internal geometry was for this purpose necessary. In our practice it were "first signs" of expansion of opportunities of use of technology of information modeling.

Besides, we develop the direction of visualization by means of BIM+Enscape and BIM+Live that allows to execute modeling and art visualization of different objects – from facades of certain buildings before building of areas with a real land relief and also to move on an object 3D model in real time using VR.

Visualization of BIM+Enscape

Vadim Kalle: In one of the most popular standards for data processing centers of BICSI (USA) it is recommended to carry out CFD modeling of work in the different modes. There are also standard report forms by these calculations. In the West use of CFD at design of DPC and server premises was widely adopted owing to indisputable advantages. In our country some customers are already familiar with the term CFD, someone specifies use of this technology as obligatory point in competitive terms of reference. But in general for Russia it is innovation so far.

What cannot be told about BIM technology which became practically the standard for the modern companies. By the way, on July 19, 2018 order^[1] of the Russian President about transition of the construction industry to technologies of information modeling by July 1, 2019 was published. It is sure that the CFD technology will develop on the way of BIM, and its application will become obligatory at design of high-responsible objects in the near future, including for justification of solutions when passing examination.