Influence Of Oil Temperature Research Articles

Analytical modeling and experimental verification of churning torque for cam guide rails of 2D piston pump

For 2D piston pump the churning torque of its cam guide rails at high speed is one of the main sources of mechanical efficiency loss. To conveniently calculate the churning torque and also provide guidance for future optimization of churning torque reduction, an accurate analytical model of constant acceleration and constant deceleration cam guide rail assembly of the stacked-rollers 2D piston pump is established, where the whole churning torque is divided into the peripheral churning torque, the pushing flow churning torque, and the end face churning torque. Then the analytical model is verified by CFD simulation preliminarily. Analytical modeling shows that at 16,000 rpm, the churning torque reaches about 0.826 N m, where the peripheral churning torque, the pushing flow churning torque, and the end face churning torque account for about 55.4%, 37.3%, and 7.3% of the total torque respectively, indicating that the structural parameters related to the pushing flow torque should be optimized with first priority at high rotational speed. Finally, the churning torque at 1000–16,000 rpm was experimentally measured and the influence of oil temperature was considered. The experimental results are in good agreement with the results of analytical modeling and CFD simulation, thus verifying the correctness of the proposed analytical model.

Development of insulation moisture level criteria as a result of technological progress in the maintenance system of oil-filled transformers

Transformers are critical elements of electrical networks and systems. The operational reliability of oil-filled transformers largely depends on the characteristics of the insulation, which is confirmed by the failure statistics. A number of factors affecting the insulation of electrical machines are identified, including excessive moisture, with its negative consequences outlined. The complexity and shortcomings of the use of traditional technologies for drying solid insulation are indicated, which focus on the search and implementation of the latest technologies in the system of maintenance and repair of transformers — automated insulation restoration systems (AIRS).Taking into account the development of technical progress in the field of service maintenance of transformers, the negative impact of moisture on the reliability, durability and overload capacity of electrical machines, especially those beyond their normal service life, a new look at the criteria for the moisture content of cellulose insulation is proposed. A review is made of the normative requirements for the moisture content of the insulation of oil-filled transformers of a number of Russian and foreign standards. On the basis of the Oommen equilibrium curves, the shortcomings of the lack of comparability of the humidity criteria for solid and liquid insulation in STO 34.01–23.1– 001–2017 and RD 34.45–51.300–97 are presented. It is proposed to single out several areas of the operational state of transformers in terms of “moisture content of solid insulation (paper)”. The optimal period for the use of AIRS has been determined.The AIRS technology is implemented in a TRANSEC module, which enables to carry out work under load, without adversely affecting predictive diagnostics. The design features of the TRANSEC module, the principle of operation, functional and design differences from standard transformer units – thermosiphon /adsorption filters — are outlined. The results of testing the TRANSEC technology in an existing electrical installation serviced by PJSC Rosseti are presented. Six months of trial operation of the TRANSEC module demonstrated the restoration of insulation characteristics on operating equipment without additional involvement of personnel. Besides, during the testing of the TRANSEC technology, the influence of oil temperature on the information content of the assessment of solid insulation parameters was confirmed. Proposals are formulated on the revision of industry documentation in the established part.

Influence of oil temperature on pressure distribution and flow force of valve core

Influence of oil temperature on pressure distribution and flow force of valve core

Influence of oil temperature on pressure distribution and flow force of valve core

Influence of oil temperature on pressure distribution and flow force of valve core

Effect of various operating parameters on the steady-state performance of the bent axis motor

The work presented in this article investigates the experimental study of the effects of various operating parameters such as oil temperature, speed, sizes and the load torque on the steady-state performance of the fixed displacement bent axis motor. In this respect, five different capacities of the motor are considered. The effects of the operating conditions and the capacities of the motor on its flow and torque-losses are identified. With an increase in pressure and temperature, gaps in the hydrostatic machine vary, and it also affects the viscosity of the fluid. The outcome of them on the performance of the motor is characterized. From the test data, a mathematical model of the losses is established that consider the influence of oil temperature, motor speed, load torque, capacities of motor and the system pressure. The model has shown good agreement with the test data; the overall efficiency of the different capacities motor at three different operating temperatures is compared. Such a model may be adapted to evaluate the performance of motor over a range of operating conditions. The proposed model may be utilized by the technocrats for selecting the bent axis motor drive for a given application.

Industrial Gear Oils: Influence of Bulk Oil Temperature and Contact Pressure on Tribological Performance and Subsurface Changes

This study was designed to investigate the influence of oil temperature and contact pressure on the tribological performance of three industrial gear oils but also on the corresponding changes taking place beneath the metal surfaces in contact. The result shows that increase in the oil temperature and contact pressure increases surface–additive interaction, promoting the formation of low-friction tribofilms. Subsurface characterisation of the worn surfaces shows that higher oil temperature and contact pressure promotes surface hardening of spheroidised AISI 52100 steel, degradation of the near-surface (< 0.8 µm) microstructural integrity and corresponds to an increase in wear. This study clearly shows that the gear oil formulations and the tribofilms they form uniquely influence the extent of subsurface deformation and wear.

Influence of Oil Temperature on the Lip Seal’s Performance

In some application fields—for example, the automotive industry—lip seals operate over a wide temperature range. Under such conditions, oil temperature plays an important role in determining the efficacy of lip seals. In order to simulate the lip seal’s behavior with ambient temperature change, this article improved the traditional simulation approach by characterizing the rubber material property regarding temperature dependency in the model. The effect of oil temperature on the sealing performance of lip seals was investigated through numerical simulation and experiments. The static contact pressure, radial force, reverse pumping rate, and friction torque were calculated as a function of oil temperature. The simulation results were verified by bench testing.

Effects of multiple parameters on static electrification and breakdown strength of transformer oil

Forced convection of insulation oil is the main heat transfer mode in large-power and ultra-high-voltage (UHV) transformers. The electrification hazard caused by physicochemical phenomena between mineral oil and pressboard has been suspected to be responsible for several failures. The electrification measurement was carried out in an oil flow system. The influences of oil temperature, flow velocity, time and applied electric field of fresh and dry transformer oil have been investigated by a measurement system. The experimental results from the oil flow system show that the streaming current increases with the increase of the temperature when the temperature is below 50°C, while it reverses when the temperature is above 50°C. The streaming current increases with the increase of AC and DC electric fields under the different flow velocities, but the streaming current polarity reverses with DC electric field polarity under the 6.9 m/s flow velocity. The electrification phenomenon can lead to reduction of the breakdown strength of the oil. It is concluded that some effective measures should be taken to restrain the possible harm caused by the streaming electrification in UHV converter transformer.

Determination of thermal conductivity and convective heat transfer coefficient during deep fat frying of “Kroštula” dough

In this study, the influence of oil temperature, water migration and surface temperature of “Krostula” dough on convective heat transfer coefficient was investigated. The convective heat transfer coefficient during deep fat frying was determined at temperatures 160, 170, 180 and 190±1 °C. Heat transfer coefficient was the highest at the start of deep fat frying process; 579.12±2.46, 583.88±1.81, 597.05±1.10 and 657.91±0.95 W/m2 K for 160, 170, 180 and 190 °C of oil temperature, respectively. The smallest heat transfer coefficient was in the case of setting up a uniform period of water migration from sample, which corresponded to surface temperatures slightly higher than 100 °C; 26.53±0.63, 14.42±0.56, 56.78±0.49 and 37.52±0.54 W/m2 K for 160, 170, 180 and 190 °C of oil temperature, respectively. Higher oil temperature for deep fat frying increased values of heat transfer coefficient. A steady-state method was used to determine thermal conductivity of “Krostula” dough in temperature range of 40–70±1 °C. The thermal conductivity first increased with temperature and then after reaching maximum values decreased. The maximum value 0.5985±0.0196 W/(m K) was determined at 47.5 °C. The minimal value 0.4723±0.0192 W/(m K) was determined at 65 °C.

Studies of Bulk Temperature and Friction Loss of Hypoid Gears (Influence of Oil Temperature)

Influences of oil temperature on the bulk temperature and friction loss of hypoid gears were investigated by means of test equipment of the power circulating type. The bulk temperature is one of the indexes of the scoring strength formula. The test results showed that the oil temperature affects on the friction loss very much and the lower the oil temperature, the lower the friction loss. It is possible to reduce the total loss of hypoid gear unit by making oil temperature low when hypoid gear unit were used in the high load. The temperature rise of hypoid gear is proportional to the frictional power loss not concerned with the oil temperature if the gear speed is constant. The empirical formula between the friction loss, oil viscosity and gear speed was obtained.

Determination of convective heat transfer coefficient during frying of potato dough

In this study, the influence of oil temperature, water migration and surface temperature of potato dough ball on convective heat transfer coefficient was investigated. The convective heat transfer coefficient during deep-fat frying was determined at temperatures 160, 170, 180 and 190 °C. The dough ball of wheat flour with different amounts of whole potato flour having a radius of 2.5 cm was used as a sample. Heat transfer coefficient was the highest at the beginning of deep-fat frying process (197.25 ± 1.39 to 774.88 ± 3.90 W/m 2 K), and the lowest in the case of setting up a uniform period of water migration from sample, which corresponded to surface temperatures slightly higher than 100 °C (94.22 ± 0.33 to 194.84 ± 0.91 W/m 2 K). Addition of whole potato flour in dough considerably decreased heat transfer coefficient regardless of the frying oil temperature. Higher oil temperature for deep-fat frying increased values of heat transfer coefficient for the same composition of spherical shape dough.

956 ハイポイドギヤの本体温度と摩擦損失に関する研究(給油温度の影響)

956 ハイポイドギヤの本体温度と摩擦損失に関する研究(給油温度の影響)

Mass and heat transfer during deep-fat frying of potato slices —I. Rate of drying and oil uptake

The influence of oil temperature, dry matter content of potato tubers and thickness of slices on drying and oil uptake during deep-fat frying of potato chips (British: potato crisps) was investigated. Experiments were carried out on a laboratory scale at strictly isothermal frying conditions, and by using uniform slices cut from potato tubers of known weight (size) and specific gravity (dry matter content). An exponential model and a multiple linear regression model was applied successfully to describe dehydration and oil uptake, respectively. Drying may be accelerated by increasing oil temperature. A higher initial dry matter content abbreviates drying time due to the start of the process at lower moisture content. As oil uptake calculated on the weight of potato chips is controlled primarily by residence time in the frying unit, final fat content is lower at higher oil temperatures and initial dry moisture contents. Oil uptake calculated on the constant basis of wet weight of raw potato slices is correlated positively to the oil temperature, to the initial dry matter content and to the inverse of the slice thickness. This indicates that oil is deposited on the surface and does not penetrate into the centre of slices to a large extent.

Investigation of static electrification phenomenon due to transformer oil flow in electric power apparatus

Experimental investigations of the factors affecting the generation and accumulation of static charges due to oil flow in electrical equipment are introduced and discussed. The influence of oil temperature, flow rate, and type and frequency of electrical field energization on streaming electrification of fresh transformer oil (Diala-B) has been investigated by a closed oil cycle. In addition, comparisons between the calculated and the measured values of the relative streaming currents are introduced. A spinning disc system is also used to investigate factors that cannot be easily investigated by the closed cycle, e.g. moisture content, antistatic additives, and the material of which the rotating disc is made. The experiments have been carried out for both fresh and aged oil within the temperature range of 20 to 80 degrees C using rotating discs made of various materials. The type of rotating disc material causes evident quantitative and qualitative changes in the measured current.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

油圧ブレーカの性能におよぼす油温の影響

油圧ブレーカの性能におよぼす油温の影響