REGULATION OF STRESS-DEFORMED STATE IN COMPRESSED ELEMENTS OF STEEL FRAMES

The article is devoted to the regulation of the stress-strain state in the compressed elements of steel frames under full operating load. It is proposed to perform reinforcement of such elements with different end eccentricities of load application by rational regulation of the stress-strain state in the reinforcement elements. It is shown that the use of SDS adjustment for frame racks increases their bearing capacity and reduces deformability and welds. The new proposed technology of SDS regulation and possible constructive decisions are offered. Numerical experiment revealed high efficiency of application of the proposed solutions during the reconstruction and reinforcement of the metal frame system. The implementation of the proposed method of SDS regulation confirmed its effectiveness.

ENERGY EFFICIENCY BASED OPERATION OF COMPRESSED AIR SYSTEM ON SHIPS TO REDUCE FUEL CONSUMPTION AND CO2 EMISSION

Energy efficiency subject has been gaining importance in maritime sector. The compressed air is a valuable energy source in operational manner, by the reason of intrinsic lack of efficiency in pressurization process. Operational pressure and leakage rate are the major variables which affect operational efficiency of the system. This study aims to reveal potential energy saving for the compressed air system. To this end, several pressure ranges, 29-30 bars to 14-18 bars, and different leakage rates 2.4% to 45% are evaluated. After the data was obtained from ships, thermodynamic calculations had been carried out. Optimization of pressure saves 47.3% in daily power requirement, 58,2% in compressed air unit cost, 18.4 and 57.4 tons of reduction in fuel consumption and CO2 emissions in a year respectively. High leakage rates can cause 2.7 times more power and fuel consumption. Finally, operating load, as an important indicator of compressor, makes imperfections identifiable.

Autonomous Energy-Efficient Complexes Based on Crude Oil for Working in Arctic Conditions

The work is devoted to solving scientific and technical problems on the development of new generation Russian power equipment. Comprehensive theoretical and experimental studies of the effect of aerodynamic and heat-mass exchange processes on the ignition and combustion of crude oil in the straitened conditions of fire-tube boilers are reviewed and described. Based on the results of the research, design developments were carried out, prototypes of a fire-tube hot-water boiler with a remoted economizer and an automated low-emission burner device were manufactured and successfully tested. The efficiency of the boiler more than 94% and the reduced level of pollutants emissions in the operating load range are confirmed.

Research of the Influence of Production Technologies on the Positioning Accuracy of a Robotic Arm for Low Handling Weights

The subject of the paper is the research of production technologies influence on positioning accuracy of a robotic arm. The aim was to find out whether different production technologies (additive and conventional) and the related design differences of the robotic arm affect its operational functionality. In the research, positioning accuracy of a robotic arm formed by 3 partial arms was specifically investigated, while the first partial arm Arm I was manufactured by two different technologies. On the robotic arm, the research was carried out in such a way that the first partial arm, Arm I, was being continuously changed and was available for research purposes in two variants. Each of the Arm I variants was manufactured using a different technology (additive and conventional) while, at the same time, the individual variants also differed in construction. The design differences of both variants were related to the production technology used. The measurement of positioning accuracy was performed with the use of two methods. Specifically, a contact and a non-contact method was used. The contact method was implemented on a 3D-measuring machine RAPID and the second contactless method was performed using an inductive sensor. The maximum working load of the robotic arm was 2 kg, so the positioning accuracy was examined at three degrees of operating load equal to 0; 50 and 100% of the maximum workload.

Laboratory tests of the hydraulic pump operating load with monitoring of changes in the physical properties

The present article deals with the physical properties monitoring of the transmission-hydraulic fluid, and changes of those properties due the operating load of the hydraulic pump in laboratory conditions. Tests of the transmission-hydraulic fluid were performed in laboratory conditions with the simulation of the operating load, so as to simulate the real conditions under which hydraulic circuit of the agricultural tractors operates. The universal transmission-hydraulic fluid was subjected to analysis, where the samples of the fluid were taken sequentially according to the chosen methodology at intervals of 250 and 500 h. The results of the present article include the evaluation of the physical properties of the fluid and the flow efficiency change of the hydraulic pump after 250 and 500 h of operation, while simulating the operation load. Based on a laboratory test, we found that after working for 500 h, the dynamic viscosity of the examined hydraulic fluid at 40°C decreased by 2.92 mPa.s and at 100°C decreased by 0.64 mPa.s. When determining the kinematic viscosity of the hydraulic fluid after working for 500 h, we recorded its decrease, namely, at a temperature of 40°C by a value of 3.37 mm2/s and at a temperature of 100°C, its value decreased by 0.77 mm2/s. In the analysis of the test oil samples, we found that the level of water contamination of the hydraulic fluid decreases with increasing number of hours worked. Specifically, the water concentration in the hydraulic fluid decreased by 0.031%. At the same time, we recorded a slight decrease in the flow efficiency of the hydraulic pump, specifically by a value of 0.03% after 500 h worked. After working 500 h, we found that the range of abrasion particles in the transmission-hydraulic fluid is within the prescribed range, which is determined by the standard D6595-00.

The Forecasting Method Of Central Air Conditioning Load: A Brief Review

Objective: In order to better understand the research results of AC load prediction and carry out new research, the Air Conditioning (AC) load forecasting method plays an important role in the energy consumption of AC. Method: This paper summarizes the methods of building AC load prediction, mainly from the impact factors of AC operating load and the methods of AC system operating load forecasting to introduce the current status of load prediction. This paper describes some studies on load influencing factors, compares the advantages and disadvantages of modeling methods for AC operation load prediction and points out the research direction of AC load forecasting. Results: The current research methods are summarized and analyzed. Traditional forecasting methods are no longer applicable to air conditioning systems. From the current research, combinatorial prediction has become a hot research object. This method combines two or more methods to reduce the prediction error and shorten the prediction time. Conclusion: This paper points out some shortcomings of the present research and the future research suggestions are given in the three aspects of sharing AC operation data, selecting the key factors of AC, and exploring the new methods.

Mastering Uncertain Operating Conditions in the Development of Complex Machine Elements by Validation Under Dynamic Superimposed Operating Conditions

Machine elements produced in large quantities undergo several development cycles and can be adapted from generation to generation. Thus, experiences from real operation can be taken into account in further development. This is not possible for innovative investment goods such as special purpose machines, as these are usually individual items. Therefore, functionality and quality of newly developed components must be assured by previous investigations.Conventional methods are inadequate at this point, as they cannot represent the actual, complex operating conditions in the later application. A reliable statement about the behavior of the system through a comprehensive validation in laboratory tests under standardized conditions is not achievable in this way due to a multitude of diversified load cases.In previous work, a method was developed to allow testing of machine elements in the laboratory under detuned operating conditions. For this purpose, disturbance variables are applied to the system using paraffin wax phase change actuators in order to simulate real operation states and to analyze the behavior of the machine element under these conditions. The investigated disturbance variables are fluctuations and asymmetries of the operating load through superimposed temperature gradients. Complex interactions between the machine element and the adjacent components or the overall system can thus be taken into account.The functionality of the methodology has been developed and briefly demonstrated so far. This paper presents the next level within the development process of the methodology. The necessary components are explained in detail and an AI black box evaluation tool is discussed. This work is based on a test bench that applies dynamically changing states of detuning under superimposed disturbances. Additionally, energy efficiency and performance of the test setup is advanced. As presented, the method opens up the possibility of validating new machine elements in the laboratory under realistic conditions.

Controlled Degradation of Lubricating Media by Means of an Accelerated Electron Beam

The article deals with the possibilities of using electron accelerator for controlled aging of lubricating media used in special vehicles. During use, e.g., in combustion engines, the lubricants get contaminated and thermo-oxidative degradation also occurs. The pilot project confirms the hypothesis that ionizing radiation makes it possible to simulate the operating load of lubricating media, which was repeatedly confirmed by long-term monitoring of changes in viscosity of statistically significant samples of motor oils used in special equipment. Preliminary test results also show that there are likely to be possibilities to influence other selected properties, such as the coefficient of friction depending on the radiation dose. The authors describe physicochemical processes during irradiation and, in the example of kinematic viscosity, present summary results for selected lubricating media.

A Toolbox of Hardware and Digital Solutions for Increased Flexibility

The power generation market has been changing rapidly with the injection of an ever increasing usage of renewable power sources. The cyclic and highly unpredictable nature of power generation output from renewable sources is forcing Gas Turbine (GT) operators to significantly increase the operational flexibility of their engines. While the industry has been, for many years, developing and fielding solutions providing increased output at the high end of the operating range, the focus has shifted recently to solutions allowing for a safe decrease of the engines’ minimum operating load. The AutoTune (AT) system was introduced at last year’s Turbo Expo conference [5], and the challenges of developing a safe Extended Turndown add-on are detailed herein. Other digital and hardware solutions presented include Part Load Performance, decreased start-up time for both simple and combined cycle units, disc cavity cooling modulation and Exhaust Bleed. Increased ramp rate is addressed with the associated significant difficulty of maintaining the mechanical integrity of the rotors and casings. PSM has been working on a toolbox of both hardware and digital solutions to increase on GT operability both on the high and low ends of the load range and the technical issues faced are described in this paper.