Oil Cooler Research Articles

New oil coolers for large-capacity turbines produced by the ural turbine works

Results of industrial application of a new oil cooler type MB-125-165 for turbines developed at by specialists of the Ural Turbine Works are presented. Its technical specifications and design features are detailed. The results of long-term (more than 10 years) usage confirm the efficiency, reliability, and environmental safety of type MB-125-165 oil coolers.

GA를 이용한 오일쿨러시스템의 최적 PI제어기 설계

This paper deals with optimum PI controller design using genetic algorithm to improve control performance and robustness for an oil cooler system. The optimum PI gain was found to minimize an object function, integrated absolute error, and to satisfy control design specifications such as overshoot and settling time based on practical transfer function of the oil cooler system. The control performance and robustness were investigated by comparing indicial responses and Bode diagram analysis with respect to three kinds of PI gains obtained from different gain decision manners. Moreover, the robustness against to input disturbances, sinusoidal wave form and abrupt single pulse, was evaluated. The computer simulation results showed that the suggested optimum gain can establish desirable control performance and strong robustness with easy design process.

Thermal–hydraulic performance of a novel shell-and-tube oil cooler with multi-fields synergy analysis

In the present paper, a novel shell-and-tube heat exchanger is proposed for the application of oil cooler. It is numerically investigated compared to a rod baffles shell-and-tube heat exchanger using the commercial software FLUENT 6.3 and GAMBIT 2.3. The results of heat transfer, flow characteristics, and comprehensive performance are analyzed for both tube-side and shell-side with verifications of correlations and experimental apparatus. For tube-side, the novel heat exchanger demonstrates evidently excellent overall performance; while for shell-side, the novel heat exchanger illustrates slightly lower comprehensive performance than the rod baffles one. The path lines, pressure field, and temperature field are analyzed and the multi-fields synergy principle is adopted to evaluate the synergy extent between velocity, temperature, and pressure fields.

오일의 유량 변화와 오프셋 스트립 휜을 고려한 오일쿨러의 복합열전달 해석

Conjugate heat transfer of an automotive oil cooler with offset-strip fins was numerically investigated to predict the performance of the oil cooler for various flow-rates. The simulations were conducted by directly modeling offset-strip fins with unstructured meshes. The incompressible Navier-Stokes equations coupled with energy equation were used for the present simulations. Heat transfer characteristics of the oil cooler was compared well with experimental results and the errors were approximately within 5 percents. It was found that the performance of the oil cooler increased as the flow-rate increased up to the flow-rate of 12 L/min, but the performance seemed to be saturated beyond a critical flow-rate, which was estimated as 15 L/min. Furthermore, it was confirmed that compared to the performance without fins, that of the oil cooler with offset-strip fins was increased by about 75 percents.

Comparison of system performance on hot-gas bypass and variable speed compressor in an oil cooler for machine tools

This paper compares the system performance for two representative capacity control schemes, hot-gas bypass and variable speed compressor in an oil cooler for machine tools. An empirical linear first-order model of each controlled system was obtained from experiments by imposing a stepwise control signal to each actuator of the system. General proportional-integral controllers are designed based on the empirical transfer function models in order to control the target temperature of the oil cooler system. The experiments of starting and thermal load change were conducted to compare their control performance with each other. Especially, coefficient of performance (COP) of the two control schemes under the partial load state was also analyzed in detail. From the analyses of experimental results, the control performance of the target temperature in the two control schemes had almost the same control accuracy of ±0.1 °C at steady state. However, the COP of a variable speed compressor was as many as five-times greater than that of hot-gas bypass in comparable minimum partial load state of 0.5 kW.

An experimental study of micromilling parameters to manufacture microchannels on a PMMA substrate

Rapidly prototyping a polymer microfluidic device is a growing interest in the application fields of the disease detection, drug synthesis, and the environmental monitoring because of the benefits of the miniaturized platforms. Micromilling is one of the micromachining methods and it has been commonly used to manufacture polymer microfluidic devices. The advantages of using micromilling for polymer microfluidic devices include faster fabrication process, lower cost, easier user interface, and being capable of fabricating complicated structures, which make micromilling a perfect candidate in rapid prototyping polymer microfluidic devices for research idea testing and validation. This aim of this study is to understand the influence of each micromilling parameter to the surface quality, followed by the factor analysis to determine the optimal cutting conditions. The parameters included spindle speed, feed rate, depth of cut, and the selection of coolant (compressed air/oil coolant), and the milled surface quality was measured by a stylus profilemeter. Polymethyl methacrylate (PMMA) is the mainstream substrate material in the microfluidics due to its excellent optical property and popularity and is used as the target substrate. The experiment results showed that using the compressed air as a coolant can deliver a better surface quality than the oil coolant, and the smallest roughness achieved was 0.13 μm with the spindle speed of 20,000 rpm, feed rate of 300 mm/min, and the depth of cut of 10 μm. Factor analysis revealed that the depth of cut has the largest impact while the spindle speed has the minimized impact to the surface quality of a micromilled PMMA substrate. To further confirm the optimal cutting conditions, another 12 reservoirs were micromilled with the optimal cutting conditions and the average roughness is 0.17 μm with a stand deviation of 0.08 μm.

Control of Pulse Fatigue Test Press of Oil Cooler Based on Repetitive Control

A repetitive control system was designed to achieve above requests, the simulation model was created in Matlab to check out its work. .then repetitive control system was also built up in Matlab, and then some simulation experiments were done to check the functions of the controller. Some experiences in design and analysis of repetitive were summarized, which can be referred by other applications.

Flash Flatness Measurement System Using Digital Dial Gauges

Batch or mass production of workpiece has raised new challenges for high-efficiency measurement, especially the measurement of flatness, which is a key parameter of machining tolerance. This paper presents a novel flatness test system utilizing array of digital micrometer gauges. The software is developed based on .NET. Experiments on oil coolers are carried out with 20 sampling points, comparison with coordinate measuring machines and the steadiness of both the single gauge and the system is presented, and the results show that the system achieves high measuring speed and high consistency.

Simulation, experimentation, and collaborative analysis of adjacent heat exchange modules in a vehicular cooling system

A cooling system consisting of several heat exchange modules is a necessary part of an automobile, and its performance has a direct effect on a vehicle’s energy consumption. Heat exchangers, such as a charged air cooler (CAC), radiator, oil cooler, or condenser have different structures and can be arranged in various orders, and each combination may produce different effects because of interactions among them. In this study, we aimed to explore the principles governing interactions among adjacent heat exchangers in a cooling system, using numerical simulation and experimental technology. 3D models with different combinations were developed, compared, and analyzed comprehensively. A wind tunnel test platform was constructed to validate the computational results. We found that the heat dissipation of the modules was affected slightly by their relative position (the rules basically comply with the field synergy principle), but was independent of the modules’ spacing within a certain distance range. The heat dissipation of one module could be effectively improved by restructuring, but with a penalty of higher resistance. However, the negative effect on the downstream module was much less than expected. The results indicated that the intensity of heat transfer depends not only on the average temperature difference between cold and hot mediums, but also on the temperature distribution.

Experimental performance comparison of shell-and-tube oil coolers with overlapped helical baffles and segmental baffles

Many research studies have been conducted on the performance of shell and tube heat exchanger with helical baffles because of its lower shell-side pressure drop, lower fouling resistance and lower operation and maintenance cost. But the extension of those studies into practical application is limited because of the additional effects caused by the small-size model. In this paper, the performance of shell-and-tube oil coolers with overlapped helical baffles and segmental baffles is compared experimentally, and both of the oil coolers are practical products. The results show that the OCHB (Oil Cooler with Helical Baffles) gets lower shell side pressure drop and higher heat transfer coefficient per unit pressure drop at fixed volume flow rate than the OCSB (Oil Cooler with Segmental Baffles). Based on the experimental data, it can be predicted that with proper design the OCHB can get better heat transfer performance than OCSB. The present studies are beneficial for the design and practical operation of OCSB and OCHB.

Study of Motor Oil Cooling at Low Reynolds Number in Multi-Port Narrow Channels

Study of Motor Oil Cooling at Low Reynolds Number in Multi-Port Narrow Channels

Application of the Gmc-1000 and Gmc-2000 Mine Cooling Units for Central Air-Conditioning in Underground Mines / Zastosowanie górniczego urządzenia chłodniczego gmc-1000 i gmc-2000 w centralnej klimatyzacji kopalń podziemnych

The paper describes the design and results of operating measurements of the GMC-1000 and GMC- 2000 Mine Cooling Units. The first part describes the design of the cooling unit and its key components: the chiller, evaporator, condenser, oil cooler, evaporative water cooler and gallery air cooler. The possibilities of use in central air conditioning systems of underground mines are described. The second part discusses the results of the workstation and operating measurements and determines the coefficients for evaluating the performance of the mine cooling unit.

Predicting the oil cooler fan performance of large-sized diesel engines by changing the outlet and torsion angles

This study analyzed how the outlet and torsion angles of an oil cooler fan in large-sized diesel engines affect the performance of the fan using a numerical analysis method. The discharge flow rate, theoretical power, and efficiency were numerically calculated at the variable outlet and torsion angles. Results showed that the discharge flow rate slightly increased with increased outlet angle, leading to increased theoretical power and efficiency. The outlet-side blade also came closer to a vertical position with smaller torsion angle for higher performance of the fan. To verify the numerical analysis results, an experiment was conducted according to AMCA Standard 210–99 and the results were compared. The performance curve of the experimental and numerical analysis results indicated about 3% error.

Cause Analysis of Plate Pitting Corrosion in Lubricating Oil Cooler of Main Equipment in Datang Weihe Thermal Power Plant

The plate heat exchanger in oil cooler of unit 2 in a thermal power plant became corrosion perforation after 2-year running, and severe pits were found on its surface. The material and scale composition of the lubricating oil cooler was analyzed, and it was found that the oil cooler was made of 304 stainless steel, instead of the 316 stainless steel provided by factory. The corrosion products on the corroded surface were composed of some characteristic elements in cooling water. The analysis suggested that the reason for corrosion perforation of the heat exchanger could be associated with its material composition, and the under scale corrosion formed under the action of scale deposition could also cause corrosion perforation and large-scale pits.

Требования к системе мониторинга технического состояния трансформатора сверхмощной дуговой сталеплавильной печи

The paper presents technical characteristics of “TAMINI” 150 MVA transformer installed at ultra-high power electric arc furnaces (EAF) – 180 of “Magnitogorsk Iron and Steel Plant” OJSC. The authors considered the auxiliary equipment design: the turns of winding regulator on load and the oil cooler. They described temporary changes of the main characteristics: currents of the primary and secondary windings, oil temperature and its moisture content at various stages of under load operation. The load variation analysis and the related test parameters analysis were carried out. The research team defined the signal list for the continuous performance monitoring system under development. The authors offered some recommendations on vibration sensors installation on the transformer and on installation of partial discharge acoustic radar sensors. On the basis of the above analysis they justified the functions of the system under development.

Experimental and CFD Investigations of Mechanical Seals under Dry/Compressed Air/Liquid Lubricating Conditions

The frictional energy produced between the interface of stationary and rotating ring increases the heat and shortens the seal service life. A test rig is developed to monitor the temperature rise for the different mechanical seals for various lubricating conditions in this work. The mechanical seals are manufactured by using carbon, SS316 and tested under dry and compressed air conditions. In this, the compressed air experimental value is compared with the computational fluid analysis (CFD) results and the same model is extended for water and Neem oil coolant. The simulated value predicts the effective coolant for seals. The results shows that the sealing pressure, sliding speed and materials used in rings would be the predominant factor for measuring the temperature rise and frictional heat generation. The heat generation is effectively reduced by blowing compressed air than the dry running of seal rings. CFD result shows water and Neem oil is effective than the compressed air as a coolant medium. The computational model takes into account of the temperature distribution within the rotating and stationary rings.

Performance of Biodegradable Palm Oil Coolant in Machining Process

Performance of Biodegradable Palm Oil Coolant in Machining Process

A study on improvement of ball screw system positioning error with liquid-cooling

The demand for higher productivity and tight part tolerances requires machine tools to have faster and more accurate feed drive systems. As tried and tested technology, ball screw drive systems are still used in a majority of machine tools due to their low cost and high degree of stiffness. A high-speed ball screw drive system generates more heat and results in greater positioning error, adversely affecting the accuracy of machined parts. In this paper, we discuss the placement of a liquid-cooling system using water, coolant oil, light oil and cutting oil as coolants in a ball screw shaft to avoid thermal errors and achieve temperature equilibrium faster. In order to estimate the positioning error and thermal distribution of the ball system and effectiveness of the liquid-cooling system, all possible heat gain-loss sources were analyzed and considered calculation factors. The following paper also presents degree of positioning error improvement when a circulation liquid-cooling system and forced liquid-cooling system were employed. When comparing the predictions and the experimental results, we can see very significant cooling performance and a high degree of consistency between prediction and reality.

Erosion Corrosion on Oil Coolers for Navy Ships

Incorrect material selection does not always lead to corrosion. In addition to an inferior selection of materials, unsuitable operating conditions and poor design also contributed to the presented failure. A combination of erosion and corrosion caused a leak in an oil cooler of a Navy ship. Because there was no welding seam between the deflectors and tube plate on the carbon steel cooler, cooling water could stream between them, and the flow rate became excessive. This caused erosion on the tube plate. In addition, the repeated change of the cooling liquid after servicing caused a uniform corrosion attack.

Exposure to polychlorinated biphenyls (PCBs) among welders in Sri Lanka

Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants with the ability to cause adverse impacts on human health and the environment. This study describes the indiscriminate use of PCB-contaminated transformer oil as a coolant in informal welding shops in Kalutara, Sri Lanka. Sixty-three welders, one each from a convenience sample of 63 welding workshops participated in the study. We administered a questionnaire and observed work practices. Sixty-two (98%) workplaces used transformer oil as the coolant in the welding equipment, 60 (95%) claiming that it was the only one available. Sixty-two (98%) did not use any protective measures when refilling coolant oil, while none of them safely disposed of the empty coolant oil containers. Only four (6%) were aware of the possible health effects of PCB-contaminated coolant oil. Health and safety measures in the work places studied were very poor. Coolant oil samples from a sub-sample of 30 welding workshops were tested for PCBs; 19 (63%) were positive. PCB-contaminated coolant oil is widely used by the welders in Kalutara without adequate precautions or safety measures.