Internal Partitions Research Articles

Influence of thermal conductivity of the partition wall on non-stationary conjugate natural convective heat exchange and temperature fields in the walls of a rectangular fuel tank

The non-stationary conjugate heat transfer in a rectangular model of a fully filled thin-walled tank, divided by an internal vertical partition wall into two compartments of 1/3 and 2/3 of the tank volume is studied numerically in the conjugate formulation. The outer surfaces of the end walls and the upper wall of the tank are heat-insulated. The lower wall suddenly warms up under the influence of a uniform heat flux. The calculations are performed at the ratio of the thermal conductivity of solid walls to the thermal conductivity of fuel λs/λf = 1041.3 and λs/λf = 1 (low-heat partition wall) and thermal parameters of fuel T1 (Prandtl number Pr = 25.66). The influence of internal vertical partitions wall on the spatial shape of convective flows and the regularities of non-stationary conjugate heat exchange is studied. The temperature fields in the liquid and in the tank walls are calculated.

Expeditious methodology for the estimation of infill masonry wall stiffness through in-situ dynamic tests

In this paper a procedure to experimentally estimate the stiffness of masonry internal partitions and infill walls is proposed with the aim of providing a practical tool to reduce uncertainties in the finite element modelling of frame buildings when partitions and infills must be included. The proposed methodology, based on in-situ impact load tests and numerical modelling, is presented. The methodology is validated through an experimental campaign on a laboratory mock-up and applied to a real reinforced concrete frame building. The proposed methodology revealed capable to provide a very accurate estimate of the infill stiffness to be adopted in the building modelling.

Восстановление сценария развития взрывной аварии расчетным методом

The consequences of a real explosive accident are considered in the article. The scenario of its development is restored based on the available data. The need for a detailed study is caused by the fact that initially the main version of the explosion and fire occurrence was a methane leak from the gas pipeline at the enterprise. Having examined the materials describing the accident consequences and considering the experience of such explosive accident investigation, it became obvious that the main cause of the explosion and fire was the emergency rupture of the propane cylinder. Four stages that accompanied gas cylinder emergency rupture are examined in detail: cylinder rupture accompanied by a characteristic sound; discharge into the room of an overheated liquid located in the cylinder in the form of a vapor mixture with small drops of liquid; explosive combustion of a propane-air mixture framing an ejection jet; fire storm spreading throughout the room. Numerical calculations of the last two stages of accident development showed that the generated explosion pressure in the emergency room corresponds to the destructions that occurred, and the heat load corresponds to the burns received by the witnesses of emergency explosion. For example, the initial stage of explosive combustion was accompanied by a short-term explosive load (lasting about 20–50 ms), which had a pronounced wave character. The maximum amplitude of the explosive pressure was approximately 5 kPa. A dynamic load with the indicated parameters can cause partial damage to the building structure and internal partitions, which occurred during the accident. The resulting wind load also had a pronounced wave character and was perceived by others as a gust of wind. Wave flow velocities did not exceed 10–15 m/s, which corresponds to the concept of «gust of wind», that was indicated by the witnesses of the accident. Comparison of the calculation results with the existing destructions and damages shows that the accidental explosion occurred according to the scenario adopted in the calculations.

SCENARIO METHODS FOR FORMING SUSTAINABLE ARCHITECTURE OF APARTMENT BUILDINGS

The article is devoted to the problem of preventing the moral aging of multifamily housing. The development of sustainable housing architecture facilitated by increasing the adaptability and transformability of architectural and planning decisions of such housing.The purpose of the study is to analyze the role of scripting methods in shaping a sustainable multi-family housing architecture. Scenarios for housing market trends are difficult to follow by extrapolation methods. Scenarios are to be created on a variant basis. The diffusion of scripting methods in architecture leads to the transformation of modern typology of buildings into an alternative methodology for their formation, based on the use of time-based models. The scenarios of possible changes in the housing architecture classified as follows. Among that are e the possibility of dividing the base apartments into parts that become independent small-sized apartments. In second - apartments and suites that are optimal for mass housing, providing the ability to combine individual apartments of a smaller size options. In third - realized the possibility of internal transformation of individual dwelling cells with a decrease in the number of rooms, or vice versa - with an increase in the size of the rooms while reducing their number in the apartment. At lust – the transformation of separate apartments on the first floors into non-residential premises with dismantling of internal partitions and redevelopment of space; the possibility for creating large halls on the first, intermediate or upper floor. Methods of creating adaptive housing architecture are within the current global movement for the formation of sustainable architecture, which, in the course of careful forecasting and design, tailored to fit the functional needs of parts of the home to changing needs. Adaptability of apartments to different scenarios of family development depends on the chosen structural system of a dwelling house. Possibilities of transformation of the space of the apartment considered taking into account planning cells with different wide step of bearing walls (steps: 6, 6.6, 7.2, 9 m). These studies, which carried out at an earlier stage of architectural development, are still relevant because architects continue to design homes, even with the use of prefabricated buildings, mainly based on the current sales situation, without taking into account the projected changes.

Analysis of temperature increase in fire-exposed internal vertical partitions with glazing

Analysis of temperature increase in fire-exposed internal vertical partitions with glazing

Expanded obsidian as a soil aerator, its porosity, physical and mechanical characteristics

Today, the decline in soil fertility progress, therefore, special attention paid to the search for new, including non-traditional sources of raw materials that allow cultivating agricultural crops. It is propose to use expanded obsidian as a soil aerator. Obsidian is a volcanic rock, consisting of volcanic glass in which water content does not exceed 1%. A characteristic feature of this stone is the ability to expand under heat treatment. The expansion of obsidian is possible to implement at temperatures of 1050… 1150 °C. It has been shown that due to obsidian expansion it is possible to obtain a light porous filler with an average density of 200… 350 kg/m3, where the heat treatment of 5… 10 mm grains should be performed under temperatures from 1050 to 1150°C, during 3…5 minutes. The mechanical strength of the expanded obsidian is due to the thickness of the internal partitions of the pores and depends on the total porosity. Increased porosity decreases the strength of the expanded obsidian grains as the internal partitions of the pores become thinner. Relatively high mechanical strength develop grains with less porosity, ie lower coefficient of expansion. At the same time, the nature of the external surface of the grain has a significant influence on the mechanical strength. The melted surface,under other equal conditions provides mechanical strength increase of the expanded obsidian.

Analysis of the influence the liquid cargo oscillations in a semi-trailer tank on the wheeled tractor motion indicators

A large amount of transport work of a wheeled tractor accounts for the transportation of liquid cargoes by tractor tanks. These tanks are different from road and rail tank containers with no internal partitions that would quench fluid fluctuations. The constant tendency to increase such freight transportation causes the appearance of negative factors affecting the driver's health and economic performance of the tractor. In the study of the influence of dynamic load on fuel efficiency, a mathematical model was used, which is capable of simulating engine operation at partial load and speed modes

Performance validation and manufacture feasibility for an advanced constructive system considering facilities integration

The growing demand to save material and energy resources, and increasing concern over environmental issues, are forcing solutions that entail a lower environmental impact of the materials and products used. This is particularly relevant for internal wall partitions which, due to their volume, greatly contribute to the environmental repercussion of buildings. A significant percentage of this impact is waste derived from the integration of plumbing and electricity installations. The present research deals with the development of a new ceramic system for partitions and internal facade sheets that enable the integration of facilities with minimum waste generation.The proposed ceramic system ensures an appropriate thermal, acoustic and mechanical performance. In addition to the design description and manufacturing process, acoustic performance is measured by empirical validation, while thermal performance by numerical simulations via the finite element method (FEM). Mechanical performance is assessed by a set of experimental tests carried out on masonry walls subject to different load types, and by FEM simulation.From the results obtained, it is possible to conclude that the innovative masonry unit fulfills all the thermal, acoustic and mechanical requirements prescribed for partition systems, even improving on the results for conventional solutions.

Методика експериментального дослідження визначення динамічних характеристик при русі колісних тракторів з агрегатами змінної маси

Today, an urgent and unresolved issue is the study of transport operations that are used in the agricultural sector, because there is a problem when studying the movement of a machine-tractor unit with trailed or semi-trailer units. This is directly related to the increase in energy saturation of wheeled tractors and, as a result, an attempt to maximize vehicle performance. The study of transport work in the transportation of liquid cargo is of great interest, where an increase in cargo transportation leads to significant instability in the operation of a wheeled tractor and a tractor tank (which is devoid of internal partitions) due to natural vibrations of the liquid. This process leads to longitudinal and lateral instability, contributes to an increase in both dynamic characteristics and emergency situations (there is an effect on the smoothness of movement, vibration load, handling and stability of the vehicle, increasing the dynamic load of the undercarriage, etc.). Therefore, to confirm the theoretical aspects of the influence of fluid oscillations in the tractor tank, experimental studies are necessary. The experimental research methodology presented in this article will allow us to determine the dynamic characteristics during transportation of trailed and semi-trailer tractor tanks during steady-state movement, as well as in transient operation modes. The practical significance of the work is to obtain experimental data on the accelerations of the studied objects at different height filling of the liquid level in the tanks.

Application of oil-products-containing water treatment sludge in wall ceramics production

The article presents the research findings concerning the usage of carbon-containing water treatment sludge of test solutions, containing emulsified oil products, in raw charge for wall ceramics production. For removing oil products kieselghur sludge was used, generated at the refined vegetable oil production at winterization stage (removing waxes and waxlike substances), thermally modified at temperature 450°C. Water treatment sludge is characterized with organo-mineral composition. It was determined that baking ceramic samples with water treatment sludge at temperature 950°C causes the oxidation of oil products with the formation of gaseous products CO, H2O and CO2, which makes ceramic materials’ structure porous, which in its turn reduces their density and improves their heating-performance characteristics. The presence of organic substances in the charge for ceramic materials creates favorable thermodynamic conditions for iron oxides reducing reactions, which contribute to the formation of low-temperature silicate melt and intensify the samples’ baking process. The wall ceramics products, obtained with the use of water treatment sludge, can be used as construction material and heat-insulating material in enclosing structures and at internal partitions installation.

Fiber-reinforced lightweight foamed concrete panels suitable for 3D printing applications

This contribution presents a set of experimental results on fiber-reinforced innovative lightweight panels (FRIL-panels) having thickness of 12mm. These panels are prepared with a peculiar foamed concrete that has a high viscosity and cohesion in the fresh state, which makes it particularly suitable for 3D printing applications. The FRIL-panels can be used for internal partitions, external infills, and suspended ceilings of buildings as more effective solutions than conventional plasterboard ones, with better thermal insulation and acoustic absorption properties due to the internal air-void microstructure. The aim of this work is to investigate the out-of-plane resistance of FRIL-panels, prepared with a density of 800kg/m3, under displacement-controlled three-point bending tests. In view of potential use in the precast industry, the FRIL-panels were placed into an accelerated concrete curing tank so as to speed up the overall production process. Modulus of rupture, ultimate deflection and collapse mode of FRIL-panels are critically analysed and discussed.

Energy and Environmental performance of a green certified office building in the hot dry climate of India

This paper applies a customised post-occupancy building performance evaluation (BPE) approach to evaluate the actual performance of a Platinum-certified green office building in the extreme hot dry climate of India from both technical and occupants’ perspectives. The in-use energy and environmental performance of the office building was examined using energy data on consumption and generation, monitoring of environmental conditions (temperature, relative humidity, CO2), along with occupant satisfaction survey. Total annual energy use of the building was measured as 100 kWh/m2/year with photovoltaic generation contributing 18kWh/m2/year. Although total annual energy use was found to be 42% less than the typical office benchmark, about 6% more energy was used than predicted. Indoor air quality was perceived to still but fresh and neither too dry nor too humid. Despite this, some spaces had relative humidity measurement over 70% for more than 50% of occupied hours. Daylight factor was consistently below 2% in many areas due to internal partitions; however, BUS survey (105 responses) results showed that 71% of occupants were satisfied with lighting quality, overall comfort and other variables. Such differences between measured and perceived indoor environment indicate the role of occupant adaptation in building performance.

Hemp-lime composite for buildings insulation: material properties and regulatory framework

The increasing demand for indoor comfort in housing sector, together with the development of environmental awareness by people and societies, is leading to a rising need of new construction materials. Research and industries are then developing materials capable of meeting environmental and technical requirements: made from renewable sources; based on natural compounds to ensure healthy indoor environment and safe disposal; having good insulation properties, especially for energy saving. A material showing these features is the hemp-lime biocomposite, a natural-based mixture made of a lime binder matrix and shives aggregate, in different proportions. This paper wants to present an overview of the most interesting material properties for the building sector and a brief regulatory framework, in order to highlight the advantages that the use of this composite for building envelopes and internal partitions may provide.

Development of ammonia mass transfer coefficient models for the atmosphere above two types of the slatted floors in a pig house using computational fluid dynamics

Ammonia emissions from animal production systems are a concern due to their potential adverse effects on the environment. It is important for governments to adjust their policies to control ammonia emissions from animal production. To evaluate and quantify emission factors, process-based modelling is a cost-effective procedure, particularly due to the complex and diverse transfer chains. During the modelling process, ammonia mass transfer coefficient is one of the key parameters to be determined. However, inconsistencies are found in widely used expressions for mass transfer coefficients in ammonia volatilization models. This study used CFD simulations to derive the mass transfer coefficients above metal and concrete slatted floor in an experimental pig houses with 12 full-scale pig pens. Five ammonia mass transfer coefficient models were selected for comparison with the models derived from CFD simulations. It was noticed that the models derived from wind tunnel/flux chamber experiments usually predicted lower values of ammonia mass transfer coefficients compared to the models developed from full-scale measurements and/or numerical modelling. Care is needed to extrapolate the relationships developed under controlled laboratory conditions to the commercial barns. The results indicated also that the ammonia mass transfer coefficient relies heavily on the airflow patterns which could be affected by the ventilation systems, location of the inlet and outlets, internal partitions, floor types etc.. This makes it very difficult to present a universal ammonia mass transfer coefficient model for pig houses.

Analysis of acoustic insulation in traditional wooden architecture hotel building

This paper presents evaluation of vibroacoustical requirements in the context of impact and airborne sound insulation in hotel building. This building represents traditional wooden architecture present in southern Poland. Similar structures can be found all around Europe in mountainous areas. Due to fact that there are little information about acoustic conditions of such buildings, this paper gives measured values of sound insulation of typical solutions used in this architecture. In order to define if requirements of current polish standard PN-B-02151-03:2015 for hotel buildings are met, impact sound level and airborne sound insulation of representative partitions were measured. Measurement conducted in presented building shows issues connected with non-sufficient airborne sound insulation of internal partitions – timber log walls. Due to its low mass and, in simplification, homogenous structure, its sound insulation is far from meeting requirements. Considering timber structural ceiling and reinforced concrete floor present in hotel building requirements of impact sound level and airborne sound insulation are met. The solution of weak acoustic conditions of walls is proposed as plasterboard pre-wall with mineral wool inside.

Optimization of transport vehicle transmission vibroacoustic characteristics

One of the main sources of vibroacoustic emissions is the transmission of a transport vehicle. Providing a high level of fuel economy performance and an acceptable level of power-train noise and vibration (NVH) is a complex engineering task and a real professional challenge for NVH specialists. The purpose of the research is to provide the required level of vibroacoustic characteristics of the transport vehicle transmission being developed at the design stage through a feasible correction of structural characteristics. To achieve this goal requires deeper understanding the dynamic phenomena of NVH, as well as expansion of the virtual design methods. We used multiphase analytical methods that allow us to estimate operation dynamics and vibroacoustic response of the transmission. Based on application of advanced CAE methods, a structural analysis and subsequent calculation of acoustic radiation is performed using the example of an automatic transmission (AT) prototype which is being developed for a vehicle of category N. The ability to control acoustic emissions is demonstrated by adjusting the structural (modal) parameters of the transmission case. Engineering solutions (configuration modifications) are being worked out to change the structural state (Limit state design) of the AT configuration (structural optimization) to ensure an acceptable level of acoustic emissions. For the gearbox in question, the first 50 waveforms (mode shapes, wave mode)were identified in the frequency range up to 8 kHz. The analysis made it possible to conclude that the greatest contribution to the integral noise level is made by wave forms at a frequency of 950 Hz, the internal partitions of the gearbox housing; at a frequency of 1324 Hz, the side walls of the shaft part of the gearbox and at a frequency of 1439 Hz are connected oscillations of the side walls and partitions between the shaft part of the gearbox and the demultiplier. To suppress these vibrations, additional finning of the partition between the shaft part of the automatic gearbox and the demultiplier was installed, as well diagonal reinforcing ribs were introduced into the design of the automatic gearbox side walls and the distributor cap. The performed measures allowed significantly reducing the integral level of acoustic pressure.

Comparison of finite and boundary element methods in problems of oscillations of a composite shell of revolution with a liquid

The phenomenon of sloshing can be described as the movement of the free surface of a liquid contained in a reservoir under the action of a suddenly applied load. H. Olsen cited the classification of free-surface fluctuations in liquids by identifying three main forms of sloshing: a) longitudinal sloshing, b) vertical sloshing c) rotating sloshing. Sloshing is a phenomenon that is found in a wide range of industrial applications: in containers for storing liquefied gas, fuel tanks of missiles and airplanes, in tanks of cargo tankers. The vibrations of the real tanks are caused by sloshing of the fluid and vibration of the elastic walls. In completely (or almost completely) filled tanks, the free surface cannot experience strong oscillations. This corresponds to the launch of the launch vehicle. However, in further stages of flight, when the level of liquid aggregate falls, the sloshing effect becomes dominant. It was repeatedly noted that powerful sloshing can lead to a violation of the flight trajectory, as happened, for example, during the launch of the Falcon 1 launch vehicle in 2006, 2007 and 2008. The next important problem in the study of the oscillations of the fuel tanks is the study of the associated hydro-elastic oscillations of the fluid interacting with the elastic walls of the tank. New analytical method and computer technology have been developed for analyzing free and forced vibrations of composite fuel tanks of missiles at different stages of flight: during overloads and in microgravity conditions, including sloshing fuel. The proposed method allows us for more accurate analysis of fuel tank oscillations, taking into account the mutual influence of elastic deformations of tank walls and tank filling levels changing during missions and the shape of the free surface of the liquid, the presence of elastic and rigid damping internal partitions, and the change in acceleration of gravity. A mathematical model has been developed for the analysis of fuel sloshing at large amplitudes. The free oscillations of the launch vehicle tanks are considered.

Review of Pedestrian Load Models for Vibration Serviceability Assessment of Floor Structures

Innovative design and technological advancements in the construction industry have resulted in an increased use of large, slender and lightweight floors in contemporary office buildings. Compounded by an ever-increasing use of open-plan layouts with few internal partitions and thus lower damping, floor vibration is becoming a governing limit state in the modern structural design originating from dynamic footfall excitations. This could cause annoyance and discomfort to building occupants as well as knock-on management and financial consequences for facility owners. This article presents a comprehensive review pertinent to walking-induced dynamic loading of low-frequency floor structures. It is intended to introduce and explain key walking parameters in the field as well as summarise the development of previous walking models and methods for vibration serviceability assessment. Although a number of walking models and design procedures have been proposed, the literature survey highlights that further work is required in the following areas; (1) the development of a probabilistic multi-person loading model which accounts for inter- and intra-subject variabilities, (2) the identification of walking paths (routes accounting for the effect of occupancy patterns on office floors) coupled with spatial distribution of pedestrians and (3) the production of a statistical spatial response approach for vibration serviceability assessment. A stochastic approach, capable of taking into account uncertainties in loading model and vibration responses, appears to be a more reliable way forward compared to the deterministic approaches of the past and there is a clear need for further research in this area.

Quality control of welding in titanium panels, made using method of diffusion welding and superplastic forming

Results of studies of nondestructive control of multilayer titanium panel, made by the method of diffusion welding and superplastic forming, are considered. By ultrasonic control of the echo method with the use of a direct piezoelectric transducer, areas on which diffusion did not occur or has not occurred completely, as well as various inclusions trapped in the welded joint area during assembly, are determined. The quality of the formation of the inner surface (corrugated sheet) can be controlled by radiographic inspection, and according to the results of the control, it is possible to detect breaks, cracks, and the violation of the shape of internal partitions that appear from a technological process failure.

Effects of Internal Partitions on Flow Field and Air Contaminant Distribution under Different Ventilation Modes.

Based on frequently used internal partitions in offices, the effects of pollutant source characteristics and an internal partition on airflow and contaminant distribution under different ventilation modes are studied in this paper. The indoor flow field measurement is implemented in a 1:1 single environmental chamber under different ventilation patterns, and then the numerical model is established. The numerical method is verified and analyzed by comparing the measured and simulated results. According to the verification results, the numerical simulation is introduced to study the influence of different supply and return air mixes and pollutant source distributions on the flow field and diffusion performance with an internal partition. The indoor flow field and concentration distribution under different conditions are compared, and the discharge efficiency under different working conditions is analyzed. The results indicate that internal partitions have a greater influence on the down-supply up-return ventilation mode than the floor-supply up-return and top-supply down-return ventilation mode. Furthermore, if the room is zoned, the effect of source position is larger under the down-supply up-return ventilation mode than under the other two modes.