Air Supply Model Research Articles

Air distribution in the room by swirl compact air jets at variable mode

Abstract In this work, the actual aspect of the creation of comfortable climatic conditions indoors due to the compressed swirl compact air streams at an alternating mode is considered. The purpose of this article is the mathematical modeling of the swirl compact air jet and getting of the analytical equations for calculation air distribution in a premise at the condition of dynamic indoor climate in compressed conditions of a premise for providing comfort people well-being. A mathematical model of air supply with the swirl compact air jets in the room has been developed. A combinatorial-logarithmic method for the graphs approximating the dependence of the relative transverse velocity of a swirl compact air jet and the correction coefficient for compression and swirling on the relative transverse coordinate has been developed.

Data-driven reconstruction of interpretable model for air supply system of proton exchange membrane fuel cell

Appropriate air supply system controller is of great significance to improve the performance of proton exchange membrane fuel cell. Most of controllers rely on the high-precision, simple, and interpretable model. It is particularly important to establish the model for the fuel cell air supply system. Since the high-precision physically interpretable control-oriented model can provide an understanding of the underlying phenomena apart from computational tractability for aerodynamic problems. Data-driven sparse identification based on auto-encoder method is proposed to establish the model. It can be divided into the four steps. Firstly, collect data from a simulation model and the actual fuel cell system, and auto-encoder network is used to discover a coordinate transformation into a reduced space. Secondly, dictionary library is constructed from candidate terms based on system analysis. Thirdly, air supply model reconstruction problem is transformed into a sparse identification problem. Finally, the developed model is verified by two datasets. Compared with other methods, the results show that mean absolute error and root mean squared error of the three variables for proposed method are the smallest under both simulation data and real data. And the reconstruction results perfectly agree with the original simulation and the real data. Especially, the proposed method can be easily extended to other system modeling studies, such as the hydrogen supply system model and thermal management system model of the fuel cell system.

Thermal Analysis and Structural Optimization of High‐Efficiency Fuel Submersible Hot Water Machine

Based on the oil quality of diesel oil, the thermal efficiency and fuel consumption of the fuel‐burning submersible hot water machine were calculated. The structure of the fuel‐burning submersible hot water machine was designed. The heat transfer calculation of the flame tube and convection surface of the high‐efficiency fuel submersible hot water machine was carried out, and the overall heat balance of the system was checked. ANSYS was used to analyze and study the mechanical and thermodynamic properties of the fuel‐based submersible hot water machine, and the simulation results were compared with the theoretical calculation results. The thermal field of the flame tube and the threaded tube was simulated, and the influence of the temperature field on the flame tube was analyzed. The changes in the total deformation and strength of the flame tube under the thermal structure coupling were studied. The thermal efficiency of oil‐fired submersible hot water machine was studied, and the relevant factors affecting the thermal efficiency of oil‐fired submersible hot water machine were put forward. The main factors affecting thermal efficiency were analyzed and mathematically modeled. The air supply model and the convective heat transfer model of the threaded tube were established. The main parameters that affected the thermal efficiency of the threaded tube were optimized. In the end, the design scheme of a high‐efficiency fuel‐type submersible hot water machine was obtained.

Relationship between manual air valve positioning, water quality and energy usage in activated sludge processes

Diffused aeration is the most implemented method for oxygen transfer in municipal activated sludge systems and governs the economics of the entire treatment process. Empirical observations are typically used to regulate airflow distribution through the adjustment of manual valves. However, due to the associated degrees of freedom, the identification of a combination of manual valves that optimizes all performance criteria is a complex task. For the first time a multi-criteria optimization algorithm was used to minimize effluent constituents and energy use by parametrizing manual valves positions. Data from a full-scale facility in conjunction with specific model assumptions were used to develop a base-case facility consisting of a detailed air supply model, a bio-kinetic model and a clarification model. Compared to the base-case condition, trade-offs analysis showed potential energy savings of up to 13.6% and improvement of effluent quality for NH4+ (up to 68.5%) and NOx (up to 81.6%). Based on two different tariff structures of a local power utility, maximum costs savings of 12800 USD mo−1 to 19000 USD mo−1 were estimated compared to baseline condition.

Mathematical Simulation of a Twisted Inlet Jet at Variable Mode with Using Various Turbulence Models

The article is devoted to the solution of actual task – the efficiency increasing of the air distribution using twisted and wall air jets to provide normative air parameters in premises . The purpose of the paper is to determin e the characteristics of air flow that is formed by twisted and flat wall jet s at alternating air flow and to obtain analytic equations for determining of needed dynamic parameters of the air jets, and also to design the mathematical model of incoming air flow at the alternating air flow . The mathematical model of air supply with twisted and wall air jets is improved. It is shown that for reaching the maximal efficiency of air distribution it is necessary to supply air by jets that intensively decay before entering into a working zone . Simulation of air flow was carried out using the computational fluid dynamic software Ansys FLUENT. Simulation of the flow are carried out by one-parameter Spalart-Allmaras turbulence model and two-parameter k –e turbulence model. Good coincidence between the results of simulation using both tur b ulence models is obtained. The graphical and the analytical dependences on the basis of the conducted experimental research, which can be used in subsequent engineering calculations, are shown. Dynamic parameters of air flow that is formed by t he twisted and wall air jets at alternating air flow has been determined. New 4D method of researches is proposed for researching of jets with alternating parameters of the air. Results of experimental investigations of air supply into the room by air distribution device which creates twisted air jets for obtaining more intensive turbulization of air flow in the room are presented. Obtained results of these investigations give possibility to realize engineer ing calculations of air distribution with twisted and wall air jets.

Research on the performance of sidewall perforated plate air supply system that suitable for prefabricated buildings

Taking the rural prefabricated residential building as research object, prefabricated sidewall partitioned perforated plate air supply model and traditional jet air supply model were established respectively. Then, CFD commercial software was used to simulate the temperature field, velocity field, formaldehyde concentration of indoor air-flow distribution of the two air supply model that mentioned above. Simulation results show that in the indoor breathing zone, the valuation index of prefabricated sidewall partitioned perforated plate air supply system, such as the velocity non-uniformity coefficient, air diffusion performance index, ventilation efficiency are entirely superior to the traditional jet air supply system. Moreover, the maximum vertical temperature gradient and maximum horizontal temperature gradient of the prefabricated sidewall partition perforated plate air supply system were also small which means the new air supply system could satisfy the indoor air quality and human thermal comfort requirements.

Modeling of air flow in industrial rooms

Abstract The article is devoted to the air distribution in a room by swirl and laying air jets. Dynamic parameters of air flow that is created due to swirl and laying air jets at their leakage in a room has been determined. The mathematical model of air supply with swirl and laying air jets in the industrial rooms is improved. Simulation of air flow is performed due to CFD FLUENT (Ansys FLUENT). Solution of the equation by using k-ε model of turbulence is presented. Dynamic parameters of air flow that is created due to swirl and laying air jets at their leakage at variable regime and creation of dynamic microclimate in a room has been determined. Results of experimental investigations of air supply into the room by air distribution device which creates swirl air jets for creation more intensive turbulence air flow in the room are presented. The results of theoretical researches of influence of dynamic microclimate to the human organism are presented.

Modelling of air flow supply in a room at variable regime by using both K - E and spalart – allmaras turbulent model

Abstract The abstract is to The article is devoted to the decision of actual task of air distribution efficiency increasing with the help of swirl and spread air jets to provide normative parameters of air in the production apartments. The mathematical model of air supply with swirl and spread air jets in that type of apartments is improved. It is shown that for reachin of air distribution maximal efficiency it is necessary to supply air by air jets, that intensively extinct before entering into a working area. Simulation of air flow performed with the help of CFD FLUENT (Ansys FLUENT). Сalculations of the equation by using one-parameter model of turbulence Spalart-Allmaras are presented. The graphical and the analytical dependences on the basis of the conducted experimental researches, which can be used in subsequent engineering calculations, are shown out. Dynamic parameters of air flow that is created due to swirl and spread air jets at their leakage at variable regime and creation of dynamic microclimate in a room has been determined. Results of experimental investigations of air supply into the room by air distribution device which creates swirl air jets for creation more intensive turbulization air flow in the room are presented. Obtained results of these investigations give possibility to realize engineer calculations of air distribution with swirl air jets. The results of theoretical researches of favourable influence of dynamic microclimate to the man are presented. When using dynamic microclimate, it’s possible to decrease conditioning and ventilation system expenses. Human organism reacts favourably on short lasting deviations from the rationed parameters of air environment.

Examining a device for air distribution by the interaction of counter non-coaxial jets under alternating mode

The research deals with the solution of the relevant problem of increasing efficiency of air distribution by the interaction of counter non-coaxial jets for providing the standard parameters of the air in industrial premises. The mathematical model of air supply by the interaction of counter non-coaxial jets in these premises was improved. It was shown that to achieve maximum efficiency of air disctribution, it is necessary to supply the air by jets that attenuate rapidly even before entering the working area. We developed and explored the structure of the air distributor with the interaction of the counter non-coaxial jets, which provides intensive attenuation of velocity and excess temperature of the resulting airflow. The specific feature of this structure is the possibility to supply two non-coaxial inflowing jets. In this way, intensive mixing of inflowing jets with the surrounding air is provided and alternating mode is maintained. The graphic dependences were plotted and the theoretical dependences based on the conducted experimental studies were derived, which may be used in further engineering calculations. The authors developed and protected by the patent of Ukraine [12] the design of air distributor for the air supply by the interaction of the counter non-coaxial jets, as well as for supplying inflowing jets in the alternating mode. The cost-effectiveness of using the air distributor with the interaction of counter non-coaxial jets was shown, compared with alternative options, and specific indicators of the air distribution efficiency were given.

A novel complex air supply model for indoor air quality control via the occupant micro-environment demand ventilation

Protection of indoor air quality and human health can be achieved via ventilation, which has becomes one of the most important tasks for sustainable buildings. This approach also requires highly efficient and energy saving methods for modern building ventilations consisting of a set of parameters of the complex indoor system. Therefore, the advancement in understanding the characteristics of various ventilation methods is highly necessary. This study presents one novel air supply model for the complex occupant micro-environment demand control ventilations, to analyze the efficiency of various ventilation types. This model is established primarily according to the momentum and mass conservations, and goal of occupant micro-environment demand, which is a complex system with the characteristics of diversity and dynamic variation. As for different occupant densities, characteristics of outdoor air supply for controlling gaseous pollutant and three basic features of outdoor airflow supply reaching occupant micro-environment were obtained. This research shows that for various types of occupant density and storey height, the rising and descending rates of the demand outdoor airflow in mixing ventilation are higher than those under displacement ventilation conditions. In addition, since the structure is better designed and sewage flow is more efficient, the mixing ventilation also requires a much higher peak demand outdoor airflow than its counterpart. The increase of storey height will lead to a decline of pollutants in the breathing zone and the demand outdoor airflow. Fluctuations of air flow diffusion caused by the change of occupant density in architectural space, will lead to variations of outdoor airflow reaching occupant micro-environment. Accordingly, it would lead to the different peak values of demand outdoor airflow, and the difference becomes even significant if the occupant density increases. The variations of the air supply and fraction of air reaching the occupant-breathing zone show the characteristics of a complex system. This research is meaningful for design and optimization of the complex indoor air environment in sustainable buildings.

Research of device for air distribution with swirl and spread air jets at variable mode

The research deals with solving the urgent problem of improving the efficiency of air distribution with the swirl and spread air jets to ensure regulatory parameters of the air in industrial premises. The mathematical model of air supply with the swirl and spread air jets in these premises is improved. It is shown that for maximum air distribution efficiency, air should be supplied with the jets that are intensively damped before entering the working area. The design of the air distributor with the formation of swirl and spread air jets, providing intense damping of the velocity and excess temperature of the resulting air flow is developed and investigated. The feature of this design is the ability to feed two supply air jets, the swirl air jet, formed after having passed through plates, and the spread air jet, which comes from the annular slot. This ensures intense mixing of supply air jets of the ambient air and provides the variable mode. Graphic dependencies are built, and theoretical dependencies are derived based on experimental studies that can be used in further engineering computations. The designs of air distributors for air supply with swirl and spread air jets and feeding the supply air jets in the variable mode are developed and protected by patents Ukraine. The economic efficiency of double-jet air distributors compared to the alternatives is shown, specific performance of air distribution is presented.