The air bypass and recirculation around the server racks is the most challenging obstacle to the efficient operation of data centers. Consequently, with the purpose of overcoming such types of challenges, Computational Fluid Dynamics (CFD) simulations and studies are employed to assess the airflow and thermal performance in data centers [20; 21; 22]. The focus on studies of the airflow and thermal performance of data center processing rooms has been increasing and has been drawing attention of researchers and policy makers alike. As such, several reviews were made in the recent years concerning the efficient thermal management of data centers [23; 24; 25], of the airflow distribution [14] and cooling strategies [23; 26]. In [22], the authors created and studied a Data Center CFD model and validated in experiments the airflow. The authors of [3] simulated the thermal distribution and the airflow to study the efficiency of the energy consumption in data centers with a reduced size. The authors of [27] proposed a simplified physical model to simulate the air and heat transfer in data centers by employing real-time sensor measurements. In [28], the authors studied the CFD of liquid rack cooling in data centers where a liquid loop heat exchanger is connected at the back of server racks. The authors of [29] aimed to find and quantify how many fan-assisted perforations represent a capable and fitting cooling system in a data center with certain amount of leakage. An study focusing on the consequences of plenum depths on the thermal management in data centers and on the air flow is made in [30]. A study focusing on several estimation metrics of the thermal management in data centers by using exergy analysis is proposed in [31]. The authors of [32] studied the thermal performance of a data center for different aisles separation and different configuration of CRAC units. An experimental study is performed in on the thermal management of small container data center with the support of CFD [33]. Several simulations are made in [34] to analyze and visualize the thermal status in data centers with the purpose of decreasing the overall energy consumption. The effect of the layout of CRAC units on the thermal management of data centers is addressed in [35]. The authors of [36] studied a fan-assisted cooling system by employing the Taguchi method in closed and open data centers. However, all the aforementioned works study a relatively simplistic data center model with a reduced number of server racks. In this study, CFD simulations of the thermal performance and airflow in a real existing data center processing facility with 208 racks were made. The physical-mathematical model relies on the equations of mass, momentum and energy conservation. The fluid in this study is air and it is modeled as an ideal gas with constant properties. The model of the effect of turbulence is made by employing a \(k\)-\(\varepsilon\) standard model. A comparison of the numerical results is made to assure with a fair certainty the details that define the air flow in the room of the data center, as well as the temperature distribution and identification of hot spots. This paper is based on the result analysis of a parametric study by CFD, comprised of four case studies. Two of these case studies have varying thermal loads along the corridors, i.e., among the server racks that are located at the end, the intersection and at the center of the corridor. The other two case studies have a constant thermal load established for all racks, one being the usual thermal load and the other the maximum thermal load. Every model was simulated under the maximum and minimum air flow velocity conditions. ANSYSTM software and the ANSYS FluentTM package software tools were used to simulate and study the airflow and heat transfer processes in the data center room.