Air Exhaust System Research Articles

An investigation on NGR failure in Indian smart cities while replacing the existing overhead lines by underground cables

Abstract Nowadays, Indian power distribution companies (PDCs) are implementing smart distribution networks. Older cities are becoming smarter as per the recent government’s policy. Existing overhead distribution lines are being replaced by underground cables as an essential criterion of a smart city. One of the main problems arising in this process is the overheating of the neutral grounding resistor (NGR) in 11 kV distribution systems, even in normal conditions. NGRs, placed inside the substations, are overloading the air conditioning and exhaust systems of the substation. Sometimes failure of the NGR occurs due to overheating. In this paper, a comprehensive investigation has been carried out to reach the roots of this problem. It is observed that long underground cables have a higher ground capacitance than overhead distribution lines. Due to the higher cable capacitance, the third harmonic current circulates through neutral, which overheats the NGR even in normal conditions. The situation becomes worse when the substation runs on diesel generators (DGs) in an isolated state under main grid failure, as a higher amount of third-harmonic current circulates depending on the type of winding and pitch factor of the DGs. Different solutions are proposed, and their advantages and disadvantages are analyzed. Finally, the rating of the NGR is modified, and louvers-cooling fan arrangement is preferred for the running substation.

Climate-smart hydroponic chamber for efficient green fodder production under resource deficit conditions of semi-arid region

The green fodder deficit is the biggest bottleneck for livestock productivity in semi-arid regions, especially for resource-poor farmers. Low-cost climate-smart hydroponic chamber (CSHC) based hydroponic fodder production provides a viable solution under such an environment. A CSHC equipped with a fan pad-based evaporative cooling system, controlled drip watering system and smart air exhaust system was designed and developed at ICAR-IGFRI, Jhansi, India with the aim of modifying the inside growth environment of the chamber for improved production of quality fodder. The developed CSHC was capable of maintaining daily average temperature and relative humidity in the range of 23-280C and 87-90%, respectively, with an average cooling efficiency of 78.3%. This efficient cooling was an outcome of specialized CSHC designed with an effective covering material (UV stabilized 200 µm LDPE), shade net with 70% shading efficiency, fan pad-based evaporative cooling system, controlled drip watering system, and smart air exhaust system; which enabled ambient environment conducive for optimum plant growth. Among the different treatment combinations of seed loading rates and soaking hours, the highest maize biomass yield of 2.58 kg/ft2 was achieved after seven days with a seed loading rate of 300 g/ft2 when the seed was soaked for 12 h. At the highest productivity of biomass, the values of dry matter, crude protein, and crude fiber contents were found as 13.51%, 13.71%, and 15.12% respectively. The benefit-cost ratio of the developed CSHC was 1.32 with a payback period of 3.12 years. The developed CSHC was found productive and profitable; hence, it can create a great impact in achieving feed security under resource deficit conditions of climate-change-affected semi-arid regions across the globe.

Aerodynamic noise and its reduction of the marine gas turbine air exhaust system.

The aerodynamic noise of pipelines is an important part of the noise of a ship's system. This paper conducted numerical investigations on the flow and acoustic characteristics of the marine gas turbine exhaust system. The near-field and far-field acoustic characteristics of the internal flow noise of the exhaust system are calculated by employing the Möhring's sound analogy method. In addition, the far-field acoustic characteristics of the external jet flow noise of the exhaust system are calculated by employing the stochastic noise generation and radiation (SNGR) method. Two kinds of protrusions are added to the main nozzle outlet to achieve noise reduction. The internal sound field of the marine exhaust system is dominated by low frequency sound sources, which are more obvious as the exhaust mass flow rate decreases. As for the external sound field of the marine exhaust system, the peak frequency of the far-field noise spectrum decreases with the decrease in the exhaust mass flow rate. The eight periodic protrusions perform better in reducing the internal aerodynamic noise of the exhaust system, while the five aperiodic protrusions perform better in reducing the external jet noise of the exhaust system.

Uncertainty analysis method of internal drag measurement for flow-through model in high-speed wind tunnel

For aircraft with complex air intake and exhaust systems, the flow-through model simulating the internal flow passage is generally used to reduce the interference of internal and external flow fields when carrying out high-speed wind tunnel tests. The drag generated by the internal flow passage needs to be accurately measured and deducted from the full-model aerodynamic force, so as to obtain the aerodynamic characteristics of the aircraft to be tested. However, the existing internal drag measurement methods do not evaluate the uncertainty of the measurement results, which leads to the failure to evaluate the reliability of the flow-through model high-speed wind tunnel test results. This paper introduces the device and measurement method of internal drag of flow-through model. Based on GUM uncertainty analysis method, the analysis method of internal drag measurement uncertainty is established through strict mathematical derivation, which provides technical support for the evaluation of internal drag measurement uncertainty.

Fire Protection and Evacuation Analysis in Underground Interchange Tunnels by Integrating BIM and Numerical Simulation

Rescue and evacuation of underground interchange tunnels after a fire are challenging. Therefore, a method of integrating building information modeling (BIM) and a fire dynamic simulator (FDS) was proposed to analyze fire characteristics and personnel escapes in underground interchange tunnels. A BIM model of underground interchange tunnels was built, and then different formats (DXF and CAD) were generated and imported into Pyrosim software and Pathfinder software. With an increase in ventilation velocity, the CO concentration and temperature downstream of the fire source increased, and visibility decreased, according to simulation results. The critical ventilation velocity was 3.6 m/s at 30 MW. Evacuation simulation results suggested that the congestion of the transverse passage was very unfavorable for personnel escape: the escape time increased by 14.9% and 20% when the interior and entrance of the transverse passage were severely congested, while a 2.5 m wide transverse passage effectively reduced the escape time. Visibility was the first indicator that it did not meet the safety of the escape. After the tunnel’s personnel have been evacuated, the air supply or exhaust system should be started, and smoke should be expelled at a higher velocity. It is necessary to clear the passageway quickly or increase the automatic firefighting facilities when congestion is severe.

Development of a new design of deironing granulated filter for joint removal of iron and ammonium nitrogen from underground water

ABSTRACT Providing the population with high-quality drinking water is one of the main state tasks. Rural water supply systems and water supply systems of small settlements in the region require special attention, namely, the development of technologies for individual, small-sized water treatment equipment, as well as equipment for collective use, designed to purify groundwater for drinking purposes. In many areas, there are groundwaters containing excess levels of several pollutants, which makes their purification much more difficult. Elimination of shortcomings in the known methods of water iron removal is possible by reconstructing existing water supply systems from underground sources in small settlements. A rational solution is to search for groundwater treatment technologies that make it possible to provide the population with high-quality drinking water at a lower cost. The result of increasing the concentration of oxygen in water was obtained in the process of modifying the filter by changing the excess air exhaust system, which was made in the form of a perforated pipeline located in the lower half of the granular filter layer connected to the upper branch pipe. At the same time, high-quality groundwater treatment, sufficient simplicity and reliability in operation are ensured, local conditions and the inaccessibility of many objects and settlements in the region are taken into account as much as possible. After the filter was upgraded, the concentration of iron decreased from 4.4 to 0.27 mg/L and ammonium nitrogen from 3.5 to 1.5 mg/L.

Study on hydrogen dispersion in confined space with complex air supply and exhaust system

The safety issue involving unplanned H2 leakage has retarded promotion of Hydrogen fuel cell vehicles (HFCVs). When an accidental leakage occurs in a relatively closed space, H2 tends to accumulate. It is necessary to obtain a better understanding of the H2 dispersion characteristics in a relatively closed space. Most studies focus on the dispersion features in a small garage, whereas few consider large underground garages with complex ventilation systems. Herein, H2 released from a pressurized tank in a real large underground garage was investigated by a two-stage computational fluid dynamics (CFD) study. An isentropic expansion model with a real gas equation of state was employed in stage (1) to estimate the source strength which can be used as inlet boundary conditions for stage (2), the dispersion stage. The CFD models were validated against the experimental results. The concentration field and flammability envelope were focused. This study provides a feasible method for assessing the risks associated with HFCVs.

Deep Learning Model for Prediction of Air Mass Deviation Faults

Major Systems of an internal combustion Engine are Air System, Fuel system, and Exhaust system. Any malfunction in these systems increases emissions. OBD legislation mandates to monitor these systems for any faults and appropriate action should be taken in case of the any faults which increase vehicle emissions. The idea of the paper is to find the Air mass flow deviation faults using datamining and machine learning based approach. Detection of fault is classifying whether system is faulty or not. Objective is to create a deep learning model using the available vehicle data to classify the system for a fault. Three main inputs for the Air Mass flow in an internal combustion Engine are1) Fresh Air which measure using Mass Air Flow sensor2) Low Pressure EGR3) High Pressure EGRDuring vehicle lifetime, due to different real vehicle operating conditions and environmental conditions, deviation in the set point of air mass flow and actual mass flow are possible to an extent, which can affect vehicle emissions. Deviation in the Air Mass flow can be caused by intake Air mass, LP-EGR, HP-EGR. The Aim of the project is to create the deep learning model for Air Mass Flow Hi and Low faults using the available data, and associate the fault to the component in the Intake Air System.

Study on fire smoke control in evacuation passageways on the top floor of an atrium involving breathing zones combined with underfloor makeup air supplementation

Atriums are characterized by the associated large vertically vertical penetrating spaces that provide favourable conditions for smoke diffusion. In case of fire, the main purpose of makeup air and smoke exhaust systems is to ensure the safety of people. Based on the evacuation behaviour of people in fire environments, the concept of available evacuation passageway (AEP) is proposed. Breathing zone combined with underfloor makeup air supplementation is proposed to realise smoke control in AEPs. During a fire, due to the stack effect, the top floor of an atrium is usually most seriously affected by smoke. Therefore, only the smoke control effect on the top floor was analysed. The effects of makeup air inlet layouts and makeup air flow rates on smoke control in an AEP were examined. The results show that when the width of the underfloor makeup air inlet is 0.2 m, the dimensions of the makeup air inlets in the breathing zone are 0.5 m × 1 m (width × height), and the distance between two adjacent makeup air inlets is 1.85 m, the makeup air distribution is most uniform and the smoke control effect is optimal. Under this arrangement of makeup air inlets, when the makeup air flow rate accounts for 90% of the smoke exhaust flow rate, the CO concentration, temperature and visibility in the AEP can all meet the relevant evacuation requirements.

Brief Discussion on Air Supply and Exhaust System and Control Mode of Scientific Research Laboratory

Brief Discussion on Air Supply and Exhaust System and Control Mode of Scientific Research Laboratory

Risk Assessment of Exposure to Carbon Monoxide in a Residential Area around Tofu Manufacturing

Introduction: The combustion process during the production of tofu leads to the release of Carbon monoxide (CO). This study aimed to analyze the environmental risks of exposure to CO in people residing near the tofu factories in Sidoarjo, Indonesia. Methods: This was an analytic study using a cross-sectional design. Data were obtained from laboratory experiments, interviews, and observations. Five locations of the tofu manufacturing areas as a research location. Results and Discussion: The average CO concentration in five locations was below the quality standard at 54.50 µg/m3. The hazard identification showed CO could have non-carcinogenic health risks. The respondents near the tofu industry inhaled 5.63 µg/kg/day CO in average. Furthermore, at all of the locations, the CO toxic agents in the air have a rate of RQ > 1. This showed that respondents with 55 kg body weight could be exposed to CO for 8 hours/day or for 312 days/ year. As a result, the exposure to CO is unsafe or likely to result in non-carcinogenic effects on the residents in the next 30 years. Conclusion: CO concentration in all tofu manufacturing areas was below the quality standard and could cause health problems. Residents around the factory are advised to avoid exhaust gas emissions from tofu factories by providing an air exhaust system. The residents also can reduce the exposure by using a mask when outdoor activity.

Influences of the optimized air curtain at subway entrance to reduce the ingress of outdoor airborne particles

It is of great significance to control the air quality of underground metro stations, especially considering their poorly ventilated environments. Existing literature mainly focuses on the removal and control of underground pollutants and seldom pay attention to the ingress effects of atmospheric pollutants (e.g., from the burning of fossil fuels, exhaust gas of vehicles, etc.) diffusion through the entrances/exits. In this study, we aim to study the reducing effects of integrated air curtain and exhaust systems on atmospheric airborne particles entering into the metro stations. Validated turbulent models were adopted for numerical simulations. The associated effects of air curtain velocity, exhaust velocity, and atmospheric wind speed were investigated. Four different installation locations of the air curtain were considered. Subsequently, monitoring, Artificial Neural Network, and air purification methods were proposed for the optimal design of integrated air curtain and exhaust system. It is concluded that an integrated air curtain and exhaust system can improve the interception efficiency on particles around 40% compared with no measure taken at the subway entrance, or it can be increased about 20% compared with only using an air curtain system (no exhaust vent) at the entrance.

PEMANFAATAN UDARA BUANG EXHAUST FAN UNTUK PEMBANGKIT LISTRIK TENAGA BAYU DENGAN PENGARUH PENAMBAHAN HONEYCOMB BERBASIS ATMEGA 2560

Energy needs are increasing from year to year in line with the increasing population,economic growth, and high energy consumption. More than 86% of the world's energy todaycomes from fossil fuels, while the world's energy demand is increasing. One of theconsiderations for overcoming pollution caused by fossil fuels is to seek alternative energysystems. More than 90% of the energy that affects greenhouse gas emissions is the result ofburning fuels globally. Exhaust Fan is a good system for wind power extraction. This air exhaustsystem is suitable for power plants with wind turbines as a drive where the resulting wind speedis higher and consistent when compared to natural wind, but has turbulent characteristics. Thiswind is not good for the wind turbine. A honeycomb is a tool used to reduce this turbulentcharacteristic. The results obtained by the addition of a hexa type Honeycomb to the exhaustfan with a speed of 6m/s using a savonius type turbine, there was a decrease in turbine speedwhich was previously unstable between 952 to 1007 rpm to 866 rpm and the generator outputpower decreased by 0.3 watts. The addition of Honeycomb makes the turbine rotate speedstable at 866 rpm and the wind flow becomes laminar.

Removing painting-generated VOCs in a commercial airplane hangar with multiple portable exhaust hoods

Ventilation is an important means of reducing the concentration of volatile organic compounds (VOCs) in airplane painting hangars. Currently both an upside-supply and floor-exhaust (UF) system and an upside-supply and downside-exhaust (UD) system are used. However, these two conventional systems have low ventilation efficiency. To improve the VOCs exhaust efficiency, this study proposed a novel upside-supply and multiple air-exhaust (UM) system. The new system delivers conditioned air through ceiling inlets, as do the UF and UD systems, but it uses multiple portable exhaust hoods to extract VOCs. The VOC emission sources move with the painting locations; in response, the exhaust hoods should also be moved so that they are adjacent to the sources. The ventilation performance of the proposed UM system, and that of the UF and UD systems, was modelled with computational fluid dynamics (CFD). In addition, the UM system was measured on site after putting it into engineering application. The results revealed that the flow pattern of the UM system is similar to that of the push-pull ventilation, and the airborne pollutants are efficiently exhausted. Both the measured and simulated VOC concentrations in the occupied zone are significantly reduced as compared with the conventional UF and UD systems.

Non-uniform Airflow Analysis of a Greenhouse Extractor Axial with Conical Diffusers using CFD Simulation

Interest in wind energy use has increased in recent years, specifically in the study field of protected agriculture. To harness residual wind energy produced in an air exhaust system, a wind energy recovery system could be installed using a horizontal axis wind turbine, designed according to airflow conditions at the system outlet. For this reason, airstream in a greenhouse exhaust system was analyzed, wherefore a set of extractors with different number and blades wide, air attack angle, angular velocity and geometry exhaust duct were designed. Subsequently, some simulations were performed by Computational Fluid Dynamics based on different boundary conditions and according two pipeline geometric configurations: with simple and double conical diffuser. 3D model resolution was based on numerically solving the Navier-Stokes equations by means of a finite volume discretization method. With this information 36 2D images of velocity contours and another 36 in 3D of the output airflow streamlines were obtained, also speed and power curves were constructed with respect to geometric model and exhaust system. Moreover, air flow, torque, and power of exhaust system were determined. Finally, opening and flow angle values inside and outside the exhaust system airstream were estimated. By implementing a waste wind energy recovery system at a greenhouse extraction system outlet, will be possible to improve the use of generated airstream, which in most cases is expelled to the outside.

МОДЕЛЬ ОБЧИСЛЕННЯ РІВНІВ ЗВУКУ ШУМУ ВІД КОМПРЕСОРНИХ СТАНЦІЙ ДЛЯ ОБГРУНТУВАННЯ ГРАНИЦЬ САНІТАРНО-ЗАХИСНОЇ ЗОНИ

This article is devoted to the study of sound levels for noise from a gas turbine plant and technological equipment of a compressor station in everyday operation, in order to assess the sustainability of the conditions of sanitary protection zones around the compressor station and in order to protect the population living near the compressor station. The main purpose of the study is to assess the compliance of the sizes of sanitary protection zones in terms of noise load on environment. The main source of noise at compressor gas-pumping stations is determined by the noise regime at the industrial site, in addition to auxiliary equipment; include gas-pumping devices, systems of technological gas discharge from the blower circuits, fuel and starting gas of gas-pumping devices. The dependence of the noise conditions at the production site and in the environment on the sound power level of gas-pumping apparatuses, the installed power of gas-turbine plants, the sound power of the turbocompressor, service life of gas-pumping apparatuses, the number of simultaneously operating gas-pumping apparatuses, the characteristics of production premises, the design of the gas-pumping apparatuses, the state of means of noise absorption of gas-pumping apparatuses. In gas turbine installations of compressor stations, intense noise occurs in the air intake and exhaust systems, in the cooling system fan, in the turbomachine housing and in the generator. To calculate the sound levels at a separate point, depending on the distance to the noise source, a model was used taking into account the effects of sound wave propagation in atmospheric air and the characteristics of the noise source, such as: directivity and spectral characteristics of radiation, the height of the source above the surface; distance from the source to the point of determining the sound level; absorption of sound in atmospheric air, depends on the frequency and parameters of the state of the atmosphere; the effect of the influence of the earth; weather effects and others. The methodology of the standard and the international method CONCAW were used based on the results of calculating sound levels at the border of the sanitary protection zone at the compressor station. The calculation results, for standard atmospheric conditions, according to the international CONCAW method indicate that at a distance of 700 m from the sound source, the sound propagation will be 50.0 dBA, which coincides with the calculation results using the standard method and also exceeds the night noise standard by 5 dBA for conditions in the residential area. Development even when only one gas compressor is in operation, which proves the relevance of studying the environmental risks of compressor stations. KEY WORDS: NOISE, ENVIRONMENTAL RISKS, NOISE SOURCE, COMPRESSOR STATIONS, GAS PUMPING UNIT, GAS PUMPING APPARATUS, SOUND.

The Evaluation of the Containment Efficacy of Semi-Rigid Isolators for Housing Cages of Laboratory Animals Infected With BSL-3 Agents.

Research animals models infected with Biosafety Level-3 (BSL-3) agents need to be housed in specialized biocontainment caging. Most of these specialized cages have input and exhaust that is high efficiency particulate air filtered and sealed to prevent escape of the BSL-3 agent. An alternative to the use of the above BSL-3 biocontainment caging is the use of a flexible film or modified semi-rigid plastic film isolator that has its own high efficiency particulate air-filtered input and exhaust and is sealed with respect to the animal room environment, thus preventing BSL-3 agent escape. Standard caging can be housed within such an isolator. Computational fluid dynamics was used to evaluate the integrity of modified semi-rigid isolators for containment of aerosolized BSL-3 agents. Three isolators were located inside an animal BSL-3 room to provide an extra tier of protection and to permit different infectious studies within the same room while reducing or eliminating the risk of cross-contamination. The isolators were sized to house caging for rabbits and smaller non-human primates such as marmosets, African greens, and macaques. Multiple case studies of failure scenarios were investigated, including isolator breaches through the plastic membrane seam separation and rips, and exhaust fan failure. Breaching the level of containment provided by the isolators required the improbable simultaneous event of a plastic membrane rip in addition to the rare malfunction of the back-up exhaust fans. Each isolator was equipped with 2 blower motors connected in parallel to a common exhaust plenum and a battery backup. Even with this rare double (simultaneous) event, the animal BSL-3 room air exhaust system was able to contain the few droplets released in the simulated computational fluid dynamics breach. The modified semi-rigid isolators with negative airflow proved safe and effective for aerosol studies using BSL-3 agents, even in the unlikely event of a breach in containment.

Analisis Troubleshooting pada Engine G3408 Generator Set Caterpillar

A research has been conducted about Troubleshooting that occurs in the Caterpillar Engine G3408 generator Set which aims to analyze the causes of the hydraulic lock and determine how to solve the problems that occur in the Caterpillar G3408 Engine Generator Set. The research method is to perform detection, diagnostic, and repair on the engine by doing a visual check, looking for the root of the problem and doing the test. The results are engine has a hydraulic lock caused by a damaged one of the components of the Air Intake and Exhaust System. The after cooler is also damaged due to its long service life, causing the coolant to enter the combustion chamber. From the overall analysis it is concluded that the cause of engine failure is one of the components is damaged due to a long service life and to overcome this is doing repair and replacement of components on the After cooler with new components and do the periodic maintenance on the Caterpillar G3408 Engine Generator Set.

Research on Densification Mechanism of Hot Isostatic Pressing Technology in Nickel-Based Superalloys for Marine Environment

Jiang, Z.; Wang, J., and Cao, D., 2020. Research on densification mechanism of hot isostatic pressing technology in nickel-based superalloys for marine environment. In: Wan, Z. (ed.), Coordinated Sustainable Development in Coastal Areas: Environment and Economy. Journal of Coastal Research, Special Issue No. 109, pp. 100–104. Coconut Creek (Florida), ISSN 0749-0208.Nickel-base superalloy is one of the major materials employed in the manufacturing process of air valve and exhaust system of diesel engine, turbine disk and blade of gas turbine and nuclear power units. The rapid development of modern marine industry is inseparable from the rapid improvement of comprehensive properties of superalloy. In this process, hot isostatic pressing (HIP) technology has been playing a significant role in the application of Nickel-base superalloy. In this paper, the research and application of HIP technology in the field of Nickel-base superalloy are herein summarized, and concluding the effect of HIP technology on densification mechanism and properties of cast superalloy.

Human anatomy education and management of anatomic specimens during and after COVID-19 pandemic: Ethical, legal and biosafety aspects

COVID-19 is an infection caused by the SARS-CoV-2 virus, initially identified in the city of Wuhan, China, in December 2019. Since then, the virus has spread to the continents, causing a major pandemic. The impacts of this pandemic on the education of human anatomy interfere in at least two aspects: (1) receiving and managing anatomical specimens in anatomy laboratories and (2) adaptations for classes on remote virtual teaching. Therefore, this study reviewed and discussed the legal and bioethical aspects, considering the scenario of a South American Country, aiming to stimulate the debate on these two relevant themes in the international community. Because of the COVID-19 pandemic and the impossibility of mass testing, anatomists and other workers in the field must deal with the risk of receiving bodies infected with SARS-CoV-2. In this situation, additional care measures in biosafety practices are essential to protect the staff. Such measures are: the bodies must be preserved by the perfusion of formaldehyde or other fixative solutions; embalming must be performed in ventilated rooms with a good air exhaust system; to avoid excessive manipulation of bodies and procedures such as pulmonary insufflation or craniotomy; and proper use of personal protective equipment, including lab coat, gloves and masks. As for exposure of body images in online classes, this review showed that there are no legal impediments to this end. However, anatomists must adopt measures aimed at protecting the memory of the deceased, such as using secure digital platforms with restricted access; family authorization/consent and student awareness.