Conference Agenda

CPS 7: Paper Session 7: Nuclear Decommissioning, Micro Jet Ventilation, & Resiliency in Facilities
Wednesday, 22/June/2022:
2:00pm - 3:30pm

Location: Provincial

Session Topics:
Track A: Industrial Ventilation for Process Applications (occupational health, environmental emissions, innovations, best practices, etc)

Track A: Industrial Ventilation for Process Applications (occupational health, environmental emissions, innovations, best practices, etc) 


Using Industrial Ventilation Strategies to Build Resiliency into Facilities to Meet the Next Epidemic

Vimaldoss Jesudhas, Mike Carl, Duncan Phillips

RWDI, Canada

An industrial ventilation system is designed to protect occupants from pollutants and odours associated with a particular process as well as meet minimum requirements for fresh clean air. However, given the frequency with which epidemics and pandemics have occurred recently, SARS, H1N1, MERS and SAR-CoV2, designing-in resiliency against the spread of infectious diseases should be considered in industrial ventilation design. Techniques like close capture, containment, flushing of occupants may protect from an industrial process, but do not necessarily protect from other occupants who may have contracted an infectious disease. In this study the ability of a typical food processing plant to reduce the spread of an infectious disease will be examined. Methods of improving the resiliency of the design will also be evaluated. These methods will include increasing the outdoor air rate, added filtration (in room or in duct) as well as more novel technologies such as ultraviolet germicidal irradiation. The typical food processing plant will be modelled using computational fluid dynamics (CFD). The ventilation system will be modelled as designed (locations, flow rates, throw distances) and with the additional mitigation methods. A pollutant source originating from the occupants will be used to represent an infectious disease. If desired this pollutant can be scaled to represent the quanta of different diseases. From the results an increased understanding of what methods work to reduce spread of infectious disease can be used to build resiliency against the next epidemic.

Experimental And Numerical Studies Of The Leakage Of Gaseous And Particulate Pollutants Through An Opening In A Depressurized Enclosure: Application To Nuclear Decommissioning

Zeinab Rida1, Eric CLIMENT2,3, Corinne PREVOST1, Thomas GELAIN1

1Institut de Radioprotection et de Sûreté Nucléaire (IRSN), France; 2Institut de Mécanique des Fluides de Toulouse (IMFT), France; 3Université de Toulouse, CNRS-Toulouse INP-UPS, France

During nuclear maintenance and dismantling operations, a dynamic confinement passing through openings is applied in order to prevent the leakage of pollutants outside depressurized enclosures and to ensure the safety of workers. The main issues of this work are to detect and to quantify the leakage of gaseous and particulate pollutants outside the depressurized enclosure through nominal or accidental openings occurring on this device; it aims also at verifying the ability of CFD (Computational Fluids Dynamics) simulations to predict these flow inversions and quantifying the backflow of pollutants by using an hybrid turbulent modelling. To that purpose, an experimental chamber with small opening on its frontal wall has been built. Laser flow visualizations and PIV measurements have shown that the presence of an additional countercurrent turbulent jet flow in competition with the mean directional opening flow is among the main causes leading to the leakage through the opening. Gas and particles tracing techniques gave experimental evidences that quantify the backflow phenomenon near the opening. Additionally, we designed a ventilated enclosure surrounding the chamber to collect the overall amount of gaseous and particulate tracers released outside the opening. Results showed that a new criterion based on the aeraulic conditions at the opening should be taken into account to ensure an efficient confinement. CFD results confirmed the ability of the hybrid model SST-DES to qualitatively predict the flow inversions and to quantify the backflow phenomenon near the opening. This model has been successfully compared with experimental results on gaseous and particulate leakage.

Micro-Jet Ventilation – A Novel Ventilation Concept For Long-Range Aircraft Cabins

Tobias Dehne1, Pascal Lange1, Daniel Schmeling1, Ingo Gores2

1German Aerospace Center (DLR), Germany; 2Airbus Operations GmbH

Novel ventilation systems for aircraft cabins have attracted the attention of scientists and aircraft manufacturers during the last years due to their potential of energy saving, enhanced thermal comfort and advantages for pre-assembled modules.

To allow for a greener and smarter testing of novel ventilation concepts for future long-range airliners, a full-scale twin aisle cabin mock-up with thermodynamically realistic boundary conditions by means of temperature-controlled fuselage elements was developed at the German Aerospace Center (DLR) in Göttingen [1]. Temperature-controlled thermal manikins allow to simulate the heat release and obstruction of real passengers. Further, a CO2 release system can be used for the exhalation of the passengers.

Crown-integrated micro-jet ventilation (MJV), well-known as ventilation system in trains, was experimentally investigated by means of velocity field measurements, high-resolution local measurement probes and tracer gas analysis under static and dynamic operational conditions for different flight phases. Modifications of MJV with different air inlet configurations, i.e. split ratio of volume flow rates and arrangement of the micro-jets, are analysed. Temperature homogeneity, local thermal comfort, heat removal efficiency, air quality (e.g. local age of air), as well as the existence and orientation of large-scale flow structures are determined to evaluate most promising configurations. First feasibility studies and preceding computational fluid dynamic analysis proved the capabilities of this concept [2].


[1] Lange; New Long-Range Cabin Mock-Up Enabling the Simulation of Flight Cases by Means of Tempered Fuselage Elements, AEC2020

[2] Schmeling; Evaluation of Thermal Comfort for Novel Aircraft Cabin Ventilation Concepts, AEC2020

Innovative Energy-Efficient Seat Ventilation Concept Using Actively Cooling Peltier Technology

Manuel Kipp, Andreas Rolle

Chair of Ergonomics, Technical University of Munich, Germany

Through local systems such as seat air conditioning, there is an opportunity to reduce overall vehicle air conditioning consumption. In 2005, the National Renewable Energy Laboratory (NERL) demonstrated that 7.5% fuel savings in the air conditioning system are possible with ventilated seats, while maintaining the same level of thermal comfort.

In cooperation with a German automotive supplier, an actively cooled air-conditioned seat was built using Peltier technology. Due to the improved cooling performance in the seat area, slightly higher vehicle interior temperatures are conceivable.

The study presented in this paper is to investigate how much energy consumption for air-conditioning the passenger compartment can be reduced while maintaining the thermal comfort of the test persons. In this context, the thermal load for three different seating concepts is to be investigated in order to define limits for comfortable and uncomfortable conditions and to show the energy consumption. On the one hand, a normal vehicle seat without seat climate control is used as a reference, as well as a seat with ventilation and a seat with actively cooled airflow. During the test scenarios, the active seats are evaluated with increasing interior temperature. Within the study, three climate scenarios are to be evaluated by means of a questionnaire for thermal comfort. The test time for each climate scenario is 20 minutes.

The results show that the thermal comfort is similar in all three scenarios. However, the new seat cooling concept with Peltier technology can save up to 42% cooling power energy of the HVAC compared to the baseline scenario. Thus, the new seat air conditioning concept can save the required cooling power energy in an electric vehicle to achieve more range.

Effects of Altitude on the Aerosol Transport Capability in a Local Exhaust Ventilation System

Sergio Augusto Caporali Filho1, Jonathan Hale2, Robert Dayringer3, Edgar Perez Matias4

1University of Puerto Rico-Medical Sciences Campus; 2ACGIH Industrial Ventilation Committee; 3ACGIH Industrial Ventilation Committee; 4University of Puerto Rico

The objective of this pilot project was to evaluate the effects that high altitudes have on the ability of two local exhaust ventilation (LEV) systems to keep aerosol contaminants from settling inside their ductwork. Current LEV design practice described in the ACGIH Industrial Ventilation Manual (IVM), provides guidelines where Minimum Transport Velocity (MTV) is kept constant regardless of the altitude where the LEV system operates. This study’s hypothesis, on the contrary, proposes that MTV must increase with altitude and that it is air velocity pressure (VP) what needs to be kept constant across different altitudes. Therefore this pilot study tested the proposed hypothesis through the comparison of two differently designed LEV systems in their ability to effectively transport standard test dust without precipitation, while both systems were fed testing dust at a constant rate in five altitudes (0, 1K, 2K, 3K, and 4K meters above sea level). The first system was designed following IVM guidelines and the second designed based on this study’s hypothesis. Each ventilation system was ran three times in each of the tested altitudes and the precipitated contaminant mass in the ductwork at the end of each run, and in each altitude, was used as an inverse measure of the degree of their effectiveness.

Finally, the effectiveness of each ventilation system was characterized, and their performance compared. Results from this study represent an important contribution towards the scientific body of knowledge in LEV systems ‘design, for industrial operations located in high altitudes around the world.