Numerical Modeling of the Ventilation System for a Cooler Room

2006 ◽  
Author(s):  
F. Cambuli ◽  
P. F. Orru` ◽  
M. T. Pilloni
Keyword(s):  
Cooling System ◽  
Fluid Dynamic ◽  
Ventilation System ◽  
Vertical Direction ◽  
Navier Stokes ◽  
Air Distribution ◽  
Air Cooling ◽  
Electronic Control System ◽  
Commercial Code ◽  
The City

The goal of the present work was to perform a thermal and fluid dynamic analysis of a refrigerated warehouse used for cheese conservation and ripening at a cheese factory close to the city of Cagliari. Air cooling is obtained by means of cooling units located under the cooler rooms ceiling, where the air distribution is realized by means of tubular pipes made of micro-porous material. An electronic control system allows keeping temperature and humidity within the desired range. As a first step, in order to verify the operation of the cooling system, an investigation was performed through a numerical simulation of the 3D and turbulent flow within the warehouse by solving the Reynolds Averaged Navier-Stokes (RANS) equations; this task was performed by employing the commercial code Fluent. The simulation allowed to represent the temperature and the velocity maps of the air flow inside the cooler room; the most relevant result mainly consists of a strong temperature gradient along the vertical direction. Some possible interventions for improving the air distribution are also suggested.

scholarly journals RESULTS OF INSPECTION OF THE STATE OF PROVIDING THE MICROCLIMATE IN THE PIG FARM WITH A NEGATIVE PRESSURE VENTILATION SYSTEM

2021 ◽  
pp. 168-177
Author(s):  
Vitalii Yaropud ◽  
Yelchin Aliyev
Keyword(s):  
Air Temperature ◽  
Negative Pressure ◽  
Cooling System ◽  
Ventilation System ◽  
Air Cooling ◽  
Negative Pressure Ventilation ◽  
Normal Limits ◽  
Air Supply ◽  
Air Cooling System ◽  
Pig Farm

The most popular microclimate system today is based on a negative pressure ventilation system. Because it is easier to use and consumes less energy than any other forced ventilation system. The purpose of the research is to inspect the room for keeping piglets on rearing with a negative pressure ventilation system to identify shortcomings and deviations of the microclimate parameters necessary for further improvement. According to the results of the inspection of the rearing room for piglets, it was found that according to the existing system of negative pressure in the rearing room for piglets, most indicators (air velocity, ammonia, carbon dioxide, hydrogen sulfide, oxygen) are within normal limits. According to the results of the inspection of the room for keeping piglets for rearing with a negative pressure microclimate system, it was found that the air temperature in the room does not meet the recommended limits and reaches 30 °C, while the maximum recommended temperature for piglets for fattening is 20 °C. The air temperature is uneven along the length of the room, which is caused by uneven air supply from the vents. According to the results of the inspection of the room for piglets with a negative pressure microclimate system, it was found that the relative humidity at the height of the animals is higher than the recommended norms and reaches 95%, while the recommended humidity for piglets for fattening is not more than 80%. According to the results of the inspection of the room for keeping piglets for rearing with a negative pressure microclimate system, it can be stated that it is necessary to improve the air cooling system and replan the ventilation ducts of the ventilation system to ensure even air flow.

Influence of sensible cooling load on indoor air distribution in an office room with ceiling cooling and mixing ventilation

2020 ◽  
pp. 1420326X2092481
Author(s):  
Xiaozhou Wu ◽  
Haichao Wang ◽  
Jie Gao ◽  
Fenghao Wang
Keyword(s):  
Air Temperature ◽  
Temperature Difference ◽  
Turbulence Intensity ◽  
Indoor Air ◽  
Cooling System ◽  
Ventilation System ◽  
Air Distribution ◽  
Cooling Load ◽  
Contaminant Removal ◽  
Vertical Distributions

A mixing ventilation system integrated with a ceiling cooling system is a potential advanced heating, ventilation and air conditioning system for modern office buildings with a high sensible cooling load. This paper presents an evaluation of the effect of sensible cooling load on the indoor air distribution in a typical office room with mixing ventilation and ceiling cooling. The vertical distributions of indoor air temperature, air velocity and contaminant (CO2) concentration were evaluated by the vertical air temperature difference, turbulence intensity and contaminant removal effectiveness. The results showed that when the chilled ceiling surface temperature was increased from 15.0°C to 23.0°C and supply air temperature was decreased from 22.0°C to 19.0°C, the average vertical air temperature difference, turbulence intensity and contaminant removal effectiveness were 0.2°C–0.3°C, 27%–32% and 0.53–0.81 as both internal and external sensible cooling loads were 41.5 W/m2. Moreover, these evaluation indices varied slightly as the external sensible cooling load was increased from 41.5 W/m2 to 69.5 W/m2, whereas they varied greatly as the internal sensible cooling load was increased from 41.5 W/m2 to 69.5 W/m2. Hence, the external sensible cooling load could slightly affect the indoor air distribution, whereas the internal sensible cooling load could clearly affect the indoor air distribution in an office room with mixing ventilation and ceiling cooling.

scholarly journals CAA of an Air-Cooling System for Electronic Devices

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Sven Münsterjohann ◽  
Jens Grabinger ◽  
Stefan Becker ◽  
Manfred Kaltenbacher
Keyword(s):  
Shear Stress ◽  
Electronic Device ◽  
Cooling System ◽  
Electronic Devices ◽  
Navier Stokes ◽  
Air Cooling ◽  
Acoustic Analogy ◽  
Shear Stress Transport ◽  
Air Cooling System ◽  
Sst Turbulence Model

This paper presents the workflow and the results of fluid dynamics and aeroacoustic simulations for an air-cooling system as used in electronic devices. The setup represents a generic electronic device with several electronic assemblies with forced convection cooling by two axial fans. The aeroacoustic performance is computed using a hybrid method. In a first step, two unsteady CFD simulations using the Unsteady Reynolds-Averaged Navier-Stokes simulation with Shear Stress Transport (URANS-SST) turbulence model and the Scale Adaptive Simulation with Shear Stress Transport (SAS-SST) models were performed. Based on the unsteady flow results, the acoustic source terms were calculated using Lighthill’s acoustic analogy. Propagation of the flow-induced sound was computed using the Finite Element Method. Finally, the results of the acoustic simulation are compared with measurements and show good agreement.

An Innovative Inlet Air Cooling System for IGCC Power Augmentation: Part III — Computational Fluid Dynamic Analysis of Syngas Combustion in Nitrogen-Enriched Air

2013 ◽  
Author(s):  
Mirko Morini ◽  
Michele Pinelli ◽  
Pier Ruggero Spina ◽  
Anna Vaccari
Keyword(s):  
Gas Turbine ◽  
Liquid Nitrogen ◽  
Cooling System ◽  
Reverse Flow ◽  
Fluid Dynamic ◽  
Molar Fraction ◽  
Pollutant Emissions ◽  
Air Cooling ◽  
Inlet Section ◽  
Turbine Inlet

In recent years, an innovative system for power augmentation has been presented by the authors. The system is based on gas turbine inlet air cooling by means of liquid nitrogen sprayers. This system is not characterized by the limits of water evaporative cooling (i.e. lower temperature limited by air saturation) and refrigeration cooling (i.e. effectiveness limited by pressure drop in the heat exchangers), but the injection of a large amount of liquid nitrogen at gas turbine inlet section can be disputable. In fact, the air composition changes, though not considerably, after nitrogen injection. The oxygen content always seems high enough to allow a regular combustion. In any case, local effects should be further investigated. In this paper, the effect of the increase in nitrogen molar fraction of combustion air is evaluated. A micro gas turbine combustion chamber geometry (i.e. a reverse flow tubular combustor) is taken into consideration since its model has been widely validated by the authors. The analyses are performed by considering two different fuels: methane (which is the design fuel) and syngas. The results are compared in terms of overall performance (e.g. TIT, pollutant emissions) and local distributions (e.g. flow fields, flame shape and position).

scholarly journals CONTAMINANT CONTROL IN INTENSIVE CARE UNIT (ICU) USING CFD MODELING

2014 ◽  
pp. 21-25
Author(s):  
TIKENDRA NATH VERMA ◽  
S.L. SINHA
Keyword(s):  
Intensive Care Unit ◽  
Intensive Care ◽  
Control Volume ◽  
Fluid Dynamic ◽  
Ventilation System ◽  
Primary Objective ◽  
Cfd Modeling ◽  
Navier Stokes ◽  
Constant Property ◽  
Healthy Environment

Computational fluid dynamic (CFD) analysis is used to simulate and compare the removal of microbes using a number of different ventilation systems in hospitals. The primary objective of ventilation system design in hospital is to place the patient at no risk of infection while hospitalization. Normally hospitals are considered to be clean and free from pathogens which are actually not true. Due to the complex environment of hospital, the effective ventilation for comfort of patients & control of infections must be given highest priority. Intensive care represents the highest level of continuing patient care and treatment. Therefore a turbulent airflow study has been performed in Intensive Care Unit (ICU) of hospital The present investigation stresses preventing airborne infections, protecting the doctor and other patient in ICU, using Computational Fluid Dynamics (CFD) software FLUENT. In which, Navier Stokes and energy equations in threedimensional co-ordinates have been solved by control volume method. The SIMPLE algorithms are used to solve these equations. Steady state, k-ε turbulence model and incompressible flow of a constant property fluid have been considered. The tracking of massless contaminated particle (infection) has also been carried out by simulation. It is observed that remote pocket of the room where air circulation is not proper, is not healthy for the patients as well as doctor. Therefore suitable ventilation arrangement must be provided for healthy environment in the hospital.

ANALYSIS OF COMPETING VARIANTS OF AIR CONDITIONING SYSTEMS WITHOUT AIR EXTRACTION FROM ENGINES AT THE STAGE OF PASSENGER AIRCRAFT ONBOARD SYSTEMS CONCEPTUAL DESIGN

2019 ◽  
Vol 6 (3) ◽  
pp. 80-85
Author(s):  
Denis Igorevich Smagin ◽  
Konstantin Igorevich Starostin ◽  
Roman Sergeevich Savelyev ◽  
Anatoly Anatolyevich Satin ◽  
Anastasiya Romanovna Neveshkina ◽  
...  
Keyword(s):  
Conceptual Design ◽  
Air Conditioning ◽  
Research University ◽  
Cooling System ◽  
Fuel Efficiency ◽  
Air Cooling ◽  
Moscow Aviation Institute ◽  
Air Conditioning System ◽  
Low Efficiency ◽  
Air Conditioning Systems

One of the ways to achieve safety and comfort is to improve on-board air conditioning systems.The use of air cooling machine determines the air pressure high level at the point of selection from the aircraft engine compressor. Because of the aircraft operation in different modes and especially in the modes of small gas engines, deliberately high stages of selection have to be used for ensuring proper operation of the refrigeration machine in the modes of the aircraft small gas engines. Into force of this, most modes of aircraft operation have to throttle the pressure of the selected stage of selection, which, together with the low efficiency of the air cycle cooling system, makes the currently used air conditioning systems energy inefficient.A key feature of the architecture without air extraction from the main engines compressors is the use of electric drive compressors as a source of compressed air.A comparative analysis of competing variants of on-board air conditioning system without air extraction from engines for longrange aircraft projects was performed at the Moscow Aviation Institute (National Research University).The article deals with the main approaches to the decision-making process on the appearance of a promising aircraft on-board air conditioning system at the stage of its conceptual design and formulated the basic requirements for the structure of a complex criterion at different life cycle stages.The level of technical and technological risk, together with a larger installation weight, will require significant costs for development, testing, debugging and subsequent implementation, but at the same time on-board air conditioning system scheme without air extraction from the engines will achieve a significant increase in fuel efficiency at the level of the entire aircraft.

scholarly journals Air circulation in a gastrointestinal light source box and endoscope in the era of SARS-CoV-2 and airborne transmission of microorganisms

2021 ◽  
Vol 09 (03) ◽  
pp. E482-E486
Author(s):  
Stanislas Chaussade ◽  
Einas Abou Ali ◽  
Rachel Hallit ◽  
Arthur Belle ◽  
Maximilien Barret ◽  
...  
Keyword(s):  
Light Source ◽  
Cooling System ◽  
Air Cooling ◽  
Airborne Transmission ◽  
Plastic Tube ◽  
Care Workers ◽  
Air Cooling System ◽  
Forced Air ◽  
Air Circulation ◽  
Closed Environment

Abstract Background and study aims The role that air circulation through a gastrointestinal endoscopy system plays in airborne transmission of microorganisms has never been investigated. The aim of this study was to explore the potential risk of transmission and potential improvements in the system. Methods We investigated and described air circulation into gastrointestinal endoscopes from Fujifilm, Olympus, and Pentax. Results The light source box contains a lamp, either Xenon or LED. The temperature of the light is high and is regulated by a forced-air cooling system to maintain a stable temperature in the middle of the box. The air used by the forced-air cooling system is sucked from the closed environment of the patient through an aeration port, located close to the light source and evacuated out of the box by one or two ventilators. No filter exists to avoid dispersion of particles outside the processor box. The light source box also contains an insufflation air pump. The air is sucked from the light source box through one or two holes in the air pump and pushed from the air pump into the air pipe of the endoscope through a plastic tube. Because the air pump does not have a dedicated HEPA filter, transmission of microorganisms cannot be excluded. Conclusions Changes are necessary to prevent airborne transmission. Exclusive use of an external CO2 pump and wrapping the endoscope platform with a plastic film will limit scatter of microorganisms. In the era of pandemic virus with airborne transmission, improvements in gastrointestinal ventilation systems are necessary to avoid contamination of patients and health care workers.

scholarly journals Experimental Investigation and Comparison of the Thermal Performance of Additively and Conventionally Manufactured Heat Exchangers

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 574
Author(s):  
Ana Vafadar ◽  
Ferdinando Guzzomi ◽  
Kevin Hayward
Keyword(s):  
Surface Roughness ◽  
Thermal Performance ◽  
Heat Exchangers ◽  
High Efficiency ◽  
Cooling System ◽  
Fluid Dynamic ◽  
Dynamic Performance ◽  
Experimental Studies ◽  
Manufacturing Method ◽  
Industrial Sectors

Air heat exchangers (HXs) are applicable in many industrial sectors because they offer a simple, reliable, and cost-effective cooling system. Additive manufacturing (AM) systems have significant potential in the construction of high-efficiency, lightweight HXs; however, HXs still mainly rely on conventional manufacturing (CM) systems such as milling, and brazing. This is due to the fact that little is known regarding the effects of AM on the performance of AM fabricated HXs. In this research, three air HXs comprising of a single fin fabricated from stainless steel 316 L using AM and CM methods—i.e., the HXs were fabricated by both direct metal printing and milling. To evaluate the fabricated HXs, microstructure images of the HXs were investigated, and the surface roughness of the samples was measured. Furthermore, an experimental test rig was designed and manufactured to conduct the experimental studies, and the thermal performance was investigated using four characteristics: heat transfer coefficient, Nusselt number, thermal fluid dynamic performance, and friction factor. The results showed that the manufacturing method has a considerable effect on the HX thermal performance. Furthermore, the surface roughness and distribution, and quantity of internal voids, which might be created during and after the printing process, affect the performance of HXs.

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