scholarly journals STUDY OF THE BEHAVIOR OF TANK TRUCK WITH LIQUID CARGO IN CURVED MOVEMENT

2021 ◽  
Author(s):  
E. Saprykin ◽  
V. Antsiferova
Keyword(s):  
Road Traffic ◽  
Stability Margin ◽  
Fire Fighting ◽  
Heavy Duty ◽  
Tank Truck ◽  
Heavy Duty Vehicle ◽  
Overturning Moment ◽  
The Stability ◽  
Two Stages ◽  
The Impact

The principles of calculating the stability margin and overturning moment to ensure the safe-ty of road traffic of a heavy-duty vehicle on curved road sections are considered. Two stages of the behavior of a fire-fighting tanker are considered: during slow sliding in a skid and the impact of the car's wheels on an obstacle, followed by overturning.

Map Width Enhancement Technique for a Turbocharger Compressor

2013 ◽  
Vol 136 (6) ◽  
Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early
Keyword(s):  
Performance Improvement ◽  
Peak Pressure ◽  
Pressure Ratio ◽  
Comparison Study ◽  
Heavy Duty ◽  
Recirculating Flow ◽  
Heavy Duty Diesel ◽  
And Performance ◽  
The Stability ◽  
The Impact

This paper presents an investigation of map width enhancement and the performance improvement of a turbocharger compressor using a series of static vanes in the annular cavity of a classical bleed slot system. The investigation has been carried out using both experimental and numerical analysis. The compressor stage used for this study is from a turbocharger unit used in heavy duty diesel engines of approximately 300 kW. Two types of vanes were designed and added to the annular cavity of the baseline classical bleed slot system. The purpose of the annular cavity vane technique is to remove some of the swirl that can be carried through the bleed slot system, which would influence the pressure ratio. In addition to this, the series of cavity vanes provides a better guidance to the slot recirculating flow before it mixes with the impeller main inlet flow. Better guidance of the flow improves the mixing at the inducer inlet in the circumferential direction. As a consequence, the stability of the compressor is improved at lower flow rates and a wider map can be achieved. The impact of two cavity vane designs on the map width and performance of the compressor was highlighted through a detailed analysis of the impeller flow field. The numerical and experimental study revealed that an effective vane design can improve the map width and pressure ratio characteristic without an efficiency penalty compared to the classical bleed slot system without vanes. The comparison study between the cavity vane and noncavity vane configurations presented in this paper showed that the map width was improved by 14.3% due to a significant reduction in surge flow and the peak pressure ratio was improved by 2.25% with the addition of a series of cavity vanes in the annular cavity of the bleed slot system.

Example of modeling the use of fire-fighting vessels

2021 ◽  
Vol 93 ◽  
pp. 183-198
Author(s):  
A. V. Kulagin ◽  
Keyword(s):  
Evaluation Criteria ◽  
Fire Fighting ◽  
Technical Equipment ◽  
Fire Extinguishing ◽  
Logical Tree ◽  
Proposed Modification ◽  
Definition Of ◽  
Two Stages ◽  
The Impact

Introduction. The article considers a systematic approach to assessing the effectiveness of the preparation and use of fire-fighting vessels. Using the Pattern method, a study of the use of a fire-fighting boat for solving problems of extinguishing fires on water transport was conducted. Goal and objectives. The purpose of the study is to improve the methodology for determining the effectiveness of the preparation and use of fire-fighting vessels according to the selected evaluation criteria, with the determination of the impact of each criterion on the overall effectiveness of fire extinguishing. Methods. In the article, the process of evaluating the effectiveness of the preparation and use of fire-fighting vessels can be divided into two stages. At the first stage, a verbal presentation of the research task is carried out with the identification of the most "weak" training measures and during the application of fire-fighting vessels using the Pattern Method. At the second stage of the study, an assessment of the state of the identified "weak" measures is carried out with the definition of measures to improve the technical readiness of the material part or organizational and technical measures during the operation of fire-fighting vessels. Results and discussion. The author obtained a particular analytical solution for improving the efficiency of operation of fire-fighting vessels for the case of using a fire-fighting boat. A method for calculating the evaluation criteria is proposed. Conclusions. Thus, the proposed modification of the model of preparation and application of fire-fighting vessels consists in the representation of organizational and technical processes in the form of a logical "tree of goals". The directions of further research in terms of the development of the results obtained in the analysis of the operation of fire-technical equipment on fire-fighting vessels and fire-fighting vessels themselves are determined. Keywords: model, system approach, analysis, pattern method, diesel, special fire extinguishing means

Map Width Enhancement Technique for a Turbocharger Compressor

2012 ◽  
Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early
Keyword(s):  
Performance Improvement ◽  
Peak Pressure ◽  
Pressure Ratio ◽  
Comparison Study ◽  
Heavy Duty ◽  
Recirculating Flow ◽  
Heavy Duty Diesel ◽  
And Performance ◽  
The Stability ◽  
The Impact

This paper presents an investigation of map width enhancement and the performance improvement of a turbocharger compressor using a series of static vanes in the annular cavity of a classical bleed slot system. The investigation has been carried out using both experimental and numerical analysis. The compressor stage used for this study is from a turbocharger unit used in heavy duty diesel engines of approximately 300 kW. Two types of vanes have been designed and added to the annular cavity of the baseline classical bleed slot system. The purpose of the annular cavity vane technique is to remove some of the swirl that can be carried through the bleed slot system, which would influence the pressure ratio. In addition to this, the series of cavity vanes provides a better guidance to the slot recirculating flow before it mixes with the impeller main inlet flow. Better guidance of the flow improves the mixing at the inducer inlet in the circumferential direction. As a consequence, the stability of the compressor is improved at lower flow rates and a wider map can be achieved. The impact of two cavity vane designs on the map width and performance of the compressor has been highlighted through a detailed analysis of the impeller flow field. The numerical and experimental study revealed that an effective vane design can improve the map width and pressure ratio characteristic without an efficiency penalty compared to the classical bleed slot system without vanes. The comparison study between the cavity vane and non-cavity vane configurations presented in this paper showed that the map width was improved by 14.3% due to a significant reduction in surge flow and the peak pressure ratio was improved by 2.25% with the addition of a series of cavity vanes in the annular cavity of the bleed slot system.

Behavior of Micro-Alloyed Steel at Thermal Treatment

2017 ◽  
Vol 265 ◽  
pp. 177-180 ◽  
Author(s):  
T.V. Shveyova ◽  
A.M. Pesin ◽  
D.O. Pustovoytov
Keyword(s):  
Heat Treatment ◽  
Thermal Treatment ◽  
Microalloyed Steel ◽  
Alloyed Steel ◽  
Heavy Duty ◽  
Heavy Duty Vehicle ◽  
Micro Alloyed Steel ◽  
The Stability

A tendency towards the growth of grain when heating is investigated and the stability against tempering alloyed and microalloyed steel. The advantage steel, microalloyed by vanadium and nitrogen is shown and their application for heavy-duty vehicle parts is recommended. The possibility of residual forging heat of forgings realization for their heat treatment is established.

An Experimental Investigation Into the Impacts of Varying the Circumferential Extent of Tip-Low Total Pressure Distortion on Fan Stability

2021 ◽  
Author(s):  
Oliver Allen ◽  
Alejandro Castillo Pardo ◽  
Cesare A. Hall
Keyword(s):  
Total Pressure ◽  
Stability Margin ◽  
Jet Engines ◽  
Stall Inception ◽  
Stall Margin ◽  
High Incidence ◽  
Circumferential Extent ◽  
Low Distortion ◽  
The Stability ◽  
The Impact

Abstract Future jet engines with shorter and thinner intakes present a greater risk of intake separation. This leads to a complex tip-low total pressure distortion pattern of varying circumferential extent. In this paper, an experimental study has been completed to determine the impact of such distortion patterns on the operating range and stalling behaviour of a low-speed fan rig. Unsteady casing static pressure measurements have been made during stall events in 11 circumferential extents of tip-low distortion. The performance has been measured and detailed area traverses have been performed at rotor inlet and outlet in 3 of these cases — clean, axisymmetric tip-low and half-annulus tip-low distortion. Axisymmetric tip-low distortion is found to reduce stall margin by 8%. It does not change the stalling mechanism compared to clean inflow. In both cases, high incidence at the tip combined with growth of the casing boundary layer drive instability. In contrast, half-annulus tip-low distortion is found to reduce stall margin by only 4% through a different mechanism. The distortion causes disturbances in the measured casing pressure signals to grow circumferentially in regions of high incidence. Stall occurs when these disturbances do not decay fully in the undistorted region. As the extent of the distorted sector is increased, the stability margin is found to reduce continuously. However, the maximum disturbance size before stall inception is found to occur at intermediate values of distorted sector extent. This corresponds to distortion patterns that provide sufficient circumferential length of undistorted region for disturbances to decay fully before they return to the distorted sector. It is found that as the extent of the tip-low distortion sector is increased, the circumferential size of the stall cell that develops is reduced. However, its speed is found to remain approximately constant at 50% of the rotor blade speed.

scholarly journals ENSURING THE STABILITY OF INTERNAL DUMPS ACCORDING TO THE RESULTS OF PHYSICAL AND MECHANICAL PARAMETERS OF SOILS

2021 ◽  
pp. 38-45
Author(s):  
Stanislav Stovpnyk ◽  
Tetiana Kosenko
Keyword(s):  
Slope Angle ◽  
Physical And Mechanical Properties ◽  
Stability Margin ◽  
Geological Structure ◽  
Fine Grained ◽  
Lower Tier ◽  
Stability Of Slopes ◽  
The Stability ◽  
The Impact ◽  
Selective Formation

Purpose. The paper considers the issues of ensuring the stability of internal dumps consisting of soft rocks. This issue is relevant because the stability of quarry boards and dumps affects the safety of work in quarries. Methodology. When assessing the stability of slopes, the method of determining the minimum coefficient of stability, equal to the ratio of restraining forces to shear forces that arise in the slope array. Findings. The calculation and assessment of the stability of the slopes of the dumps are carried out on the example of Malyshevsky rutile-zircon-ilmenite deposit. The geological structure of the deposit overburden is represented by loess-like loams, red-brown clays, gray-green clays, fine-grained sands. To ensure the stability of internal dumps, the selective formation of dumps is proposed, which is presented in this paper in two ways. In the first variant, the dumping of Sarmatian gray-green clays into the lower part of the heap, which are weakly permeable and have low strength, is considered. In the second variant, a layer of Sarmatian sands is poured into the base of the dump. According to the normative value of the coefficient of stability margin, depending on the physical and mechanical properties of the rocks that make up the array, the optimal height and slope angle of the dump are determined. When assessing the stability of the slopes of the dump, the impact of groundwater and the possibility of location in the developed space of the tailings were also taken into account. Originality and Practical implications. Studies have shown that the most rational option is the formation of internal heaps with embedding in the base of the lower tier of the heap with a height of 40 m layer of Sarmatian sands; in the case of embedding in the lower part of the inner heaps of gray-green clays, it is advisable to form the lower tier of the heap with 2 sub-tiers up to 20 m high; the upper tier of the dump is recommended to be formed by one massif 26 m high. Besides, in the produced space of the quarry, the location of the tailings is possible in case of dumping Sarmatian sands into the base of the dump.

The Effect of Technological Parameters on the Quality of UHMWPE Products

2013 ◽  
Vol 752 ◽  
pp. 233-240
Author(s):  
Imre Kállai
Keyword(s):  
Life Span ◽  
Research Work ◽  
Heavy Duty ◽  
Technological Parameters ◽  
Quality Properties ◽  
Joint Implants ◽  
The Stability ◽  
The Many ◽  
The Impact

We can encounter products made from UHMWPE in many different areas of utilization. This material is used in plastic bearings, ball-and-socket joints, heavy-duty plastic cog-wheels and joint implants. The UHMWPE is a very particular polymer, the special characteristics of which can be attributed to its molecular structure. The ulra-high molecular weight has an effect on wear-resistance, creep-resistance and hardness. These are the parameters demanded by the highly specialized utilization. On the other hand, this molecular stucture also has disadvantages next to the many advantages. Its greatest disadvantage is that it’s difficult to process. The UHMWPE is a thermoplastic, but because of the long molecular chains its injection molding is impossible. In the course of the present research work we will compare the mechanical and quality properties of products made with lathe machining (RAM extrusion) and direct compression molding. We will examine the impact of the changes of the manufacturing and technological parameters. We will be placing a special emphasis on the surface quality because the quality and life-span of the abovementioned products (bearings, ball-and-socket joints, artficial joints) largely depends on this parameter. Besides this we will examine the changes of hardness and the stability of size. In view of these results we will try to determine what would be the best manufacturing technology that could ensure the maximum performance and life-span of these products. [1,3,6] We are focusing by having the results, to optimizing the manufacturing.

Assessment of forces and means for extinguishing fires in settlements and methods of their justifications

2021 ◽  
Vol 91 ◽  
pp. 95-106
Author(s):  
V. A. Sednev ◽  
◽  
N. V. Lopukhova ◽  
A. V. Smurov ◽  
◽  
...  
Keyword(s):  
Water Supply ◽  
Local Governments ◽  
Large Scale ◽  
Methodological Approach ◽  
Fire Fighting ◽  
Fire Season ◽  
Rural Settlements ◽  
Urban Settlements ◽  
The Stability ◽  
The Impact

Introduction. Climate change leads to an increase the number of wildfires and fires in settlements, with 74 % of the country's population living in urban settlements and 26 % in rural settlements. The readiness of localities for the fire season is determined by regulatory documents that do not assess the sufficiency of measures taken by local governments to prepare territories for the fire season, and, accordingly, do not provide protection of localities from the fires. At the same time, there is no scientific and methodological approach for determining the necessary and sufficient number of fire-fighting constructions and assessing the stability of their structure to protect settlements from the effects of mass or large-scale fires. The purpose of the study. The purpose of the study is to ensure the protection of settlements from the impact of mass or large-scale fires. Research methods. To obtain the results, general scientific and special methods of scientific knowledge were used: analysis, synthesis, generalization. They were based on the provisions of the theory of systems, theory of information. The results of the study. The forces and means that can be used to extinguish fires in localities are evaluated, and the main methods used to justify the elements of the fire-fighting water supply system in localities are considered and summarized. Conclusion. There is a contradiction between the need to ensure the protection of settlements from the impact of mass or large-scale fires and the lack of scientific and methodological approach of justification of corresponding set of means and their management. The results of the study are the basis for the development of a scientific and methodological approach to assessing and justifying the forces and means to ensure the protection of settlements from the impact of mass or large-scale fires and the safety of their activities. Keywords: locality, mass or large-scale fire, fire-fighting water supply, methods of justification

High Aspect Ratio Blading in an Axial Compressor Stage

2017 ◽  
Author(s):  
Tobias Schmidt ◽  
Markus Peters ◽  
Peter Jeschke ◽  
Roland Matzgeller ◽  
Sven-Jürgen Hiller
Keyword(s):  
Reynolds Number ◽  
Aspect Ratio ◽  
Axial Compressor ◽  
Stability Margin ◽  
Chord Length ◽  
Compressor Stage ◽  
The Stability ◽  
The Impact ◽  
Length Reduction ◽  
Profile Loss

This paper majorly aims to identify and understand the driving flow phenomena when the blading aspect ratio of a 1.5-stage axial compressor is increased so that its overall axial length is reduced. The blading is representative for a state-of-the-art high-pressure compressor (HPC) front-stage design. As part of the investigation steady-state RANS simulations are performed to evaluate the impact on its performance and operability. Moreover, an optimized high aspect ratio (HAR) design is introduced to recover performance penalties. In order to achieve the desired reduction in axial stage length at constant blade row spacing and blade height, numerous possible combinations of increased rotor and stator aspect ratios exist. The impact on compressor efficiency and surge margin will be more or less severe, depending on the chord length reduction in rotor and stator. One intermediate combination of both changes in rotor and corresponding stator aspect ratio is analyzed in detail. The results show that by reducing rotor chord length, the compressor’s stability is predominantly compromised, whereas a shorter stator chord has a bigger impact on efficiency than the rotor. For each HAR configuration, profile loss is increased through a reduced blade chord Reynolds number and a higher profile edge thickness-to-chord ratio. Secondary loss is significantly reduced. However, this effect is extenuated by an increased endwall boundary layer thickness-to-chord ratio. Ultimately, this yields a diminished overall stage efficiency. In general, current HPC blade designs exhibit a lower initial rotor aspect ratio compared to the stator vanes. Consequently, an equivalent stage length reduction has a less crucial impact on Reynolds number — hence profile loss — for rotor blades than for stator vanes. Thus, regarding efficiency, there is an optimum of balancing rotor and stator chord length reduction yielding the least efficiency drop. On the contrary, the stability margin for the compressor stage analyzed is primarily driven by the rotor’s clearance-to-chord ratio. Hence, at constant tip clearance an increase in the rotor’s aspect ratio is proportional to the resulting lack of stability. However, specific compressor design modifications are introduced in order to recover the stability margin without adversely affecting design point efficiency, such that the optimized HAR compressor stage exhibits at least the same performance specifications of the baseline design. This study’s findings also encourage that increasing the blading aspect ratio is a feasible measure for reducing the compressor’s overall axial length aiming a compact design. An optimized HAR compressor allows additional design flexibility, which provides potential for performance improvements.

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