Oil Cooler Research Articles

Increasing the Power Generation by Raising the Capacity of the Thrust Bearing Oil Cooling System in Hydroelectric Power Plants

Cooling capacity decreases due to faults appearing over time in the thrust bearing oil cooling systems of hydroelectric power plants and cooling process cannot proceed sufficiently. For this reason, while the turbine-generator unit generates energy, the thrust bearing heats up. This temperature problem prevents the unit from operating at full capacity and therefore decreases in energy production. Producing deficient energy in hydroelectric power plants, which is a renewable energy source, causes long-term economic losses for countries. In this study, the thrust bearing cooling system of a vertical Francis turbine, which produces 150 MW of energy per hour, is investigated. The reduction in the cooling capacity over time in turbine thrust bearing cooling system is solved by using exchanger system with additional plate and the power produced by the turbine-generator unit is increased 15 MW/h. This improvement has greatly contributed to the national economy. The method of increasing the cooling capacity applied to the hydroelectric power plant thrust bearings can be applied to all hydraulic turbines. This method will increase the energy production amount of the unit by approximately 10% and it costs approximately 80% cheaper than completely replacing the existing cooling system.

Use of experimental and numerical simulation methods for rational design of the air cooling apparatus for lubrication systems of compressors

The objective of the present work was to study heat and hydraulic parameters of an air cooling apparatus of oil (ACAO), whose geometry of its flow-through part is changed to decrease hydraulic losses in its air conduit and to increase the cooling efficiency of oil. Using numerical simulation methods of heat transfer, we have developed and tested the computational techniques applied in a wide class of heat exchange apparatuses, including those consisting of the sections of finned flat tubes manufactured by extrusion with subsequent deforming cutting. We have proposed to make a finned part of a heat-exchange surface in the form of porous inserts. This has allowed us to reduce numerical simulation equipment requirements and to decrease computational time. Predicted results well agree with experimental data; their analysis shows that the calculated value of thermal performance of the oil cooler due to the revealed construction drawbacks of the air conduit is by 19 % less than that of the designed one. Based on the results of the numerical simulation studies, a number of recommendations have been made how to improve the layout inside the air cooling apparatus for oil in order to enhance its thermal performance and aerodynamic quality. In particular, we have proposed to mount new fan blades to enhance its performance; to change the construction of the air outlet valve by taking away a baffle that partially overshadows the exit area of the bottom fan; to modify the shape of the bottom collector of the oil cooler in order to make a uniform velocity profile at the entrance of cooling sections. Connecting in series heat exchange sections may be a perspective engineering decision. The outcomes of all proposed engineering decisions can be assessed by numerical simulation methods that will allow us not to design expensive equipment.

Three Dimensional Simulation and Experimental Study of a Loop Thermosyphon for High Temperature Oil Cooling

The loop thermosiphon for high temperature oil cooling is a high-performance cooling heat exchanger capable of rapidly cooling high-temperature oil by transferring a large amount of thermal energy through boiling and condensation of the working fluid even with a small temperature difference. The loop thermosyphon for high-temperature oil cooling consists of an evaporation unit, an insulation unit, and a condensing section. A 3D simulation and experimental studiss were conducted simultaneously. In this study, the size of the loop thermosyphon for oil cooling is 500mm wide, 70mm long, and 1,100mm high. In addition, the size of the heat transfer tubes of the heat exchanger is 15 mm in diameter and 1,000 mm in length, and 98 heat transfer tubes were installed. The inside of the condensing unit was constructed with heat transfer tubes equipped with high-efficiency insert devices to increase the heat transfer surface area of the heating medium in the heat transfer tubes and low fin shapes were enchased on the outside of the heat transfer tubes with form rolling to increase the heat transfer surface area in contact the fluid inside the cylinder. R134a refrigerant was used as the working fluid of the loop thermosyphon to experiment changes in the temperature of the cooling air outside the condensing unit and the temperature of the refrigerant, and heat transfer performance in relation to mass flow changes and the experimental results were compared with the results of the 3D simulation. According to the results of this study, the rate of transfer of the thermal energy supplied by the evaporation unit of the loop thermosyphon heat exchanger for high-temperature oil cooling and the rate of transfer of the thermal energy absorbed by the air in the condensing unit matched well within the range of ±5%. Therefore, the reliability of the experimental results of this study was verified. In addition, thanks to the heat transfer tubes equipped with high-efficiency insert fins installed inside the condensing unit of the loop thermosiphon for high temperature oil cooling, the condensation heat transfer performance of the condensing unit increased significantly compared to that of condensing units made with flat plates.

The effect of different coolants on emissions and fuel consumption of a diesel engine

A diesel engine performance test system is set up based on the AVL framework, and an experimental investigation is conducted to evaluate the effects of three coolants on the diesel engine coolant outlet temperature, lubricating oil temperature, exhaust emissions and fuel consumption under real engine conditions. The results show that when the coolant circulating temperature is 80 °C, the exhaust temperature of the diesel engine using C-PG (anhydrous propylene glycol) coolant is the lowest, and the lubricating oil temperature is increased by 5 °C. Thus, when the coolant circulating temperature is 95 °C, the C-PG coolant is used. The outlet temperature and the lubricating oil temperature are similar to those of the other two coolants. The nitrogen oxides (NOx) emission of the diesel engine using C-PG coolant is slightly higher than that with the other two coolants, while the soot, carbon monoxide (CO) and hydrocarbon (HC) emissions are reduced. Finally, when the coolant circulating temperature is 95 °C, the fuel consumption using the C-PG coolant and L2 lubricating oil is reduced by 3.8%, compared with the C-EG (mixture of water and ethylene glycol) coolant and L1 lubricating oil.

PENGARUH VARIASI JENIS PENDINGIN DAN KEDALAMAN POTONG PADA PROSES BUBUT BAJA ST60 TERHADAP UMUR PAHAT

Turning machining process is a warkpiece diameter reduction by using chisel cut to produce the shape of the workpiece on a turning, there are various types of machining turning chisel pieces on the turning chisel types include carbide, CBN, and insert. There are also other types on conventional chisel on a turning process, one of which is a turning type of high speed steel (HSS), the turning is widely used in coventional production processes for other than low cost is also easy to grinding. Parameter in this research is coolant and depth of cut. The coolant used is dromus, ex-oil, ex cooking oil. The depth of cut used is 0,3mm, 0,5mm amd 0,8mm. The highest of tool life in this reserch with dromus as coolant at 0,3mm depth of cut is 83,17 minutes. With ex-oil at 0,3 depth of cut the tool life is 70,79 minutes. And with ex-cooking oil the tool life is 56,77 minutes with 0,3mm depth of cut. While the lowest tool life be obtained with ex-cooking oil coolant at 0,8mm depth of cut is 38,90 minutes. So, the canclusion dromus is a batter then ex-oil and ex-cooking oil. This is caused when the dromus as coolant can mixed with water and become one so can get down temperture of chisel.

Non-Traditional Machining Process of Composite Materials using Renewable Lubricants

The global increasing alertness of the environmental and health problems linked to the use of mineral based metal cutting fluids in machining is lead industry to develop alternative fluid. The fluid should be environmentally friendly and sustainable like vegetable oil with suspended nanoparticle. The low thermal conductivity of cutting fluids of natural based oil requires the addition of nanoparticles. The most common nanoparticle that suitable to be added to cutting fluid are non-metals, carbide, oxide, Carbon Nano Tubes (CNTs) and metal nitrides. In this paper, a comparison had made of dry machining and machining with cutting coolant oil, sunflower oil+MoS2, Sunflower, oil Graphene. The study concludes that, the addition of such minerals to the cutting fluids increased the thermal conductivity of cutting fluids.

Improving heat exchanger efficiency using the pulsed method of cleaning

The fouling of heat exchange equipment leads to serious economic losses in many industries, therefore to find a method to reduce deposits on heat transfer surfaces remains an actual task. In this paper, a practical solution is proposed for the implementation of a pulsating cleaning method of oil coolers as an example. The influence of pulsations on cleaning of the external surface of the heat exchanger is studied by computer modeling with Ansys Fluent. The fluid flow was described by the Navier-Stokes equation, particle motion and their interaction was described by the discrete element method (DEM). In the study, a staggered tube bundle was considered. The pulse frequency 0,3125 Hz, the amplitude referred to the diameter of tube is 35, the Reynolds number 100, the duty cycle of the pulsations 0,25. Oil was chosen as the medium. Evaluation of the pulsating cleaning method was carried out on the basis of the analysis of the mechanics of particle collisions on the surface of the central cylinder in the beam, with stationary and pulsating flow. It was found that the pulsating flow helps to reduce deposits in the front of the cylinder and is not effective in the back. An analysis of the mechanics of particle impact on the heat exchange surface showed that this pulsation mode is more effective for removing plastic deposits.

Improving heat exchanger efficiency using the pulsed method of cleaning

The fouling of heat exchange equipment leads to serious economic losses in many industries, therefore to find a method to reduce deposits on heat transfer surfaces remains an actual task. THE PURPOSE. In this paper, a practical solution is proposed for the implementation of a pulsating cleaning method of oil coolers as an example. METHODS. The influence of pulsations on cleaning of the external surface of the heat exchanger is studied by computer modeling with Ansys Fluent. The fluid flow was described by the Navier-Stokes equation, particle motion and their interaction was described by the discrete element method (DEM). In the study, a staggered tube bundle was considered. The pulse frequency 0.3125 Hz, the amplitude referred to the diameter of tube is 35, the Reynolds number 100, the duty cycle of the pulsations 0.25.Oil was chosen as the medium. RESULTS. Evaluation of the pulsating cleaning method was carried out on the basis of the analysis of the mechanics of particle collisions on the surface of the central cylinder in the beam, with stationary and pulsating flow. It was found that the pulsating flow helps to reduce deposits in the front of the cylinder and is not effective in the back. CONCLUSHION. An analysis of the mechanics of particle impact on the heat exchange surface showed that this pulsation mode is more effective for removing plastic deposits.

Development and Performance Evaluation of Eco-Friendly POSS-Containing MQL Oil Coolant for Drilling Processes

Drilling work on Inconel, a well-known super-heat-resistant alloy, requires a significant quantity of cutting oil to prevent heat-induced abrasion and damage to the cutting tool, caused by the strength and toughness of the alloy. This high requirement of cutting oil, however, negatively affects the processing environment; therefore, minimum-quantity lubrication (MQL), an eco-friendly cutting-oil-supply method, is attracting attention. The conventional MQL method, however, has the disadvantage that an oil-mist is produced along with high-pressure air; hence, the mist is scattered in the air, making the application of the oil to the cutting point inefficient and rendering the cooling effect to be less than that in wet processing. In this study, therefore, an eco-friendly compound, polyhedral oligomeric silsesquioxane (POSS)—a nanostructured organic–inorganic hybrid material that exhibits better adhesion to materials than conventional MQL-specific oil and is resistant to the heat generated during drilling—was developed by adding POSS to the conventional MQL-specific oil, and the effects were verified.

The Significant Study of using Vegetable Oil as a Cutting Lubricant on Conventional Lathe Machine

The occurrence of tool wear in machining is a natural phenomenon that cause failure. The deformation during cutting at the interface between the tool face and workpiece tends to generate high cutting temperature. The application of flood coolant to reduce the friction at the tool-work piece may create several environmental problems. The introduction of Minimum Quantity Lubrication (MQL) as an alternative technique which is the process of pulverizing a very small amount of oil (< 30ml/h) can be regarded as replacement of dry machining while it may also be considered as an alternative to flood cooling. The effect of vegetable oil lubricant and cutting speed on tool wear and surface integrity were the research scope. Three machine speed; 120, 141, and 174 m/min were used in the experimental setup on mild steel and carbon steel on work material using cemented carbide tools. The result of surface roughness and tool wear using canola oil mixing with 2 weight percent (wt%) of Zinc-dialkyl-dithio-phosphate (ZDDP) were compared against synthetic oil coolant. Comparison results show that canola oil mix can perform better compare to the synthetic oil coolant in term of surface finish. From tool wear perspective, canola oil mix show 26.5% smaller area compare to the synthetic oil coolant.

Experimental investigation on shell-side performance of a novel shell and tube oil cooler with twisted oval tubes

The lubrication oil cooler is widely used in many industries. The lubrication oil is usually operated in a laminar state with Reynolds number less than 1000 due to its high viscosity characteristic. It is hard to augment the heat transfer performance of high viscosity fluids without obvious pressure drop. A lot of researches have been conducted on the shell-side heat transfer and fluid flow characteristics of twisted oval tube heat exchangers. However, the previous study mainly focused on the high Reynolds number regime and the correlations obtained are not suitable for low Reynolds flow. In the present paper, a novel self-supported shell-and-tube oil cooler with twisted oval tube bundles (OCTT) is designed. Experiments are conducted to investigate the shell-side heat transfer and pressure drop of OCTT compared to the conventional shell-and-tube oil cooler with round tube bundles (OCRT) in low Reynolds number flow. The experimental results indicate that at identical oil volume flow rate, the shell-side pressure drop of OCTT is lower than that of OCRT. Furthermore the shell-side heat transfer coefficient per unit pressure drop of OCTT is larger than OCRT. The empirical equations for Nusselt number and friction coefficient of OCTT in low Reynolds number ranging of 50–600 are also deduced from the experimental data, which could provide a beneficial guidance for the design of OCTT.

Performance analysis of plate-fin heat exchanger used for case drain oil cooling application in variable displacement pumps

Variable displacement pumps are commonly employed in fluid power equipment. In applications involving variable displacement pumps, overheating of oil is a frequently encountered problem necessitating an effective oil cooling solution. In this work, the thermo-hydraulic performance analysis of an air blast hydraulic oil cooler, which is a compact heat exchanger (Brazed Aluminium Plate-Fin type) with surface heat enhancement feature in the form of rectangular offset strip fins is presented. The performance models available in the literature present correlations for f and j factors limited to a particular surface geometry and Reynolds number Re range. In the present work a detailed theoretical thermo-hydraulic analysis of an existing heat exchanger is presented using models available in the literature and also experimentally validated using a developed test-rig. The performance parameters derived from f and j factors like exchanger effectiveness, heat transfer coefficients and pressure drop are amply addressed. It was found that, cooler effectiveness varied only slightly with increasing oil inlet temperatures; whereas effectiveness decreased with increasing flow rates. The heat transfer rates increased with increasing oil flow rates and also with increasing oil inlet temperatures. The pressure drop on the oil side was found negligible.

АНАЛИЗ МЕТОДОВ ПРОЕКТИРОВАНИЯ ОХЛАДИТЕЛЕЙ СИСТЕМ ОБЕСПЕЧЕНИЯ ТЕПЛОВОГО РЕЖИМА СУДОВЫХ ЭНЕРГОУСТАНОВОК

The design methods for shipboard shell-and-tube oil and water coolers are presented. As a result of the review, it was revealed that currently there is no systematic and complete methodological support for the integrated computer-aided design of ship heat exchangers (CAD SHE), which in turn would be integrated into the CAD / CAM / CAE system and later on into the production preparation. From the analysis it follows that not all operating conditions of ship power plants are provided with an oil cooler. This is due to the fact that the surface of the cooler and its flow characteristics were calculated only on the nominal mode, and other operating characteristics were not evaluated. The complexity of the work of ship oil and water coolers lies in the fact that the parameters of the heat load on these devices change, the temperature and salinity of the outboard water change depending on the navigation area. Determining the effect of the oil cooler on changing the power of the power plant when the characteristics of the cooling coolant (seawater) change, such as initial temperature, flow rate, salinity, without additional testing in each mode is difficult. It is also difficult to change the salinity and temperature of the seawater during the tests. Thus, the designer of the power plant does not know how the mode of its operation will change when the ship (ship) in the World Ocean is different. This indicates the need to improve the methods of thermal and hydrodynamic calculations of SHE with their integration into the overall design system. Under these conditions, the problem of using integrated CAD SHE is of particular relevance.

BASIC RESEARCH METHODS OF COOLANT GAS DYNAMICS IN COOLING SYSTEM ELEMENTS OF HIGH-POWER GENERATORS

In given scientific work, the peculiarities of thermal calculation of high-power Turbogenerators are considered. The possibility of operation of the unit with the clogged oil cooler is shown. The main temperatures of design elements the Turbogenerator rated 200 MW are indicated.

Enhancement of Machining Accuracy Utilizing Varied Cooling Oil Volume for Machine Tool Spindle

In this study, varied cooling oil volume (VOV) control was developed for the oil coolant of a machine tool. This allows adjustment of the oil circulation flow rate in terms of the machining loads and rotational speeds of the spindle to remove the generated heat effectively from the spindle. A mathematical model of the cooling oil flow rate in terms of the rotating speed and torque of the spindle for VOV method is developed. From the thermal deformation experiments with the VOV method, the thermal deformations in both the Y-axis and Z-axis can be greatly reduced, by 70.1 % and 73.5 %, respectively, in variable rotational speed operation with a short operational period (10 minutes). Moreover, the VOV method was applied to shorten the required warm-up time of the spindle. The required warm-up time of the spindle can be shortened by 50 %, while the three axes of the spindle attain stable thermal conditions. In practical machining experiments, the machining accuracy with the VOV method can be greatly enhanced by 34 % to 62 % in comparison with the current case of constant cooling oil volume (COV). The VOV control system in the machine tool spindle can effectively reduce the thermal deformation and shorten the required warm-up time. In addition, the machining accuracy can be greatly enhanced.

Comparison of Additively Manufactured Louvered Plate-Fin Heat Exchangers

Abstract Additive manufacturing (AM) enables improved heat exchanger (HX) designs where performance is based on the achievable geometry. However, consequences of the AM process that affect HX performance such as increased surface roughness, dimensional tolerance issues, and defects like cracks may vary among identically designed AM parts due to AM machine settings. This paper experimentally compares the thermal and hydraulic performance of three AM HXs built using a traditionally manufactured, stamped aluminum oil cooler design. The AM HXs exhibited significantly higher air-side pressure drop and higher heat transfer rate than the traditional HX in large part due to increased AM surface roughness. Among AM HXs, one AM HX had notably higher heat transfer rate and air-side pressure drop due to poor print quality on the thin air-side fin features. The fin thickness among AM HXs also varied by about 15%, and there were only slight differences in surface roughness. This study indicates that functional HXs built using AM vary in performance even when the same digital model is used to print them and that AM HXs as a group can perform considerably differently than their traditional counterparts.

КАЧЕСТВО РАБОЧЕГО ПРОЦЕССА, ЭКСПЛУАТАЦИЯ И РЕСУРСНЫЕ ВОЗМОЖНОСТИ СОВРЕМЕННОГО ВСПОМОГАТЕЛЬНОГО ДИЗЕЛЯ С ЭЛЕКТРОННЫМ УПРАВЛЕНИЕМ

The article focuses on the general characteristics of the new generation electronically controlled marine diesel engine Caterpillar С-9. The principles of operation and composition of the elements involved in the organization of the workflow, monitoring and diagnostics of engine parameters in operation have been listed. There has been presented a schematic circuit of the engine electronic control system, which includes a hydraulic pump to activate the injection process, circulation lubrication pipeline, fuel filter, oil filter, oil cooler, nozzles. The recommended schedule of preventive inspections and repairs of Caterpillar C9 diesel engine has been analyzed; its environmentally friendly characteristics have been evaluated. There was made the comparison of the changes of workflow parameters of Caterpillar C9 diesel engine with S20 Sulzer diesel engine with conventional control under different loads. The results of long-term operation of both diesel engines are given; structural shortcomings associated with the insufficient quality of many component parts are analyzed. High requirements for fuel quality and purification have been mentioned. The engine has no indicating instrumentation, diagnostics of failure of any element or system, as well as its elimination is performed only by a service technician who can enter the database. Practical examples of the repeated failures in the engine computer control system of the tanker “Marine Alliance” and attempts to reveal their sources are specified in the senior engineer’s report. The structural complexity of fuel supply elements and engine workflow control systems along with the dependence of the engine team on the service center lead to difficulties in operation, significant financial costs and reducing engine operational time.

Control and measurement systems for spark ignition rotary engine

To precisely control and measure the performance of a single-rotor spark ignition rotary engine, a control system and measurement system were developed. A redundant design for hardware and software of sensors was applied. A symmetrical layout formed by two crankshaft position sensors was used to generate square wave signals that were complementary and inputted into the electric control unit as the crankshaft position reference. The corresponding software timing strategy and fault diagnosis were designed. Based on a simulation test and engine bench test, the electric control system shows a reasonable control effect, and the engine performance parameters including output torque, intake air flow and pressure, fuel and oil consumption, cooling air and coolant flow, and excess air ratio indicate that the engine control system and measurement system can operate smoothly.

Multi-Scale CFD Modeling of Plate Heat Exchangers Including Offset-Strip Fins and Dimple-Type Turbulators for Automotive Applications

Plate heat exchangers including offset-strip fins or dimple-type turbulators have a wide application in the automotive field as oil coolers for internal combustion engines and transmissions. Their optimization is a complex task since it requires targeting different objectives: High compactness, low pressure drop and high heat-transfer efficiency. In this context, the availability of accurate Computational Fluid Dynamics (CFD) simulation models plays an important role during the design phase. In this work, the development of a computational framework for the CFD simulation of compact oil-to-liquid heat exchangers, including offset-strip fins and dimples, is presented. The paper addresses the modeling problem at different scales, ranging from the characteristic size of the turbulator geometry (typically µm–mm) to the full scale of the overall device (typically cm–dm). The simulation framework is based on multi-scale concept, which applies: (a) Detailed simulations for the characterization of the micro-scale properties of the turbulator, (b) an upscaling approach to derive suitable macro-scale models for the turbulators and (c) full-scale simulations of the entire cooler, including the porous models derived for the smaller scales. The model is validated comparing with experimental data under different operating conditions. Then, it is adopted to investigate the details of the fluid dynamics and heat-transfer process, providing guidelines for the optimization of the device.

Design analysis and performance evaluation of heat pipe embedded oil cooler with enhanced staggered fins

Hydraulic coolers are most commonly preferred cooling source in industry. The progress in past few years have offered high efficiency and reliable hydraulic component, yet hydraulic cooling circuit design is often neglected part of development. One aspect of the hydraulic cooling circuit design is prevention of overheating hydraulic oil. Allowing oil temperature rise beyond particular limit can increase the power consumption and reduce the life of a system due to poor lubrication, higher internal leakage, higher risk of cavitation’s and damage component. Now-a-days shell and tube type oil coolers with water as the cooling medium are used as hydraulic oil cooler, these are extremely bulky and running cost is high hence it is needed to be replaced by another system that will be air cooled to make provision for lower space consumption and cost reduction. This paper discusses the design and development of innovative oil cooler heat extraction system using heat pipe. Designs of fins preferred are namely the straight fin system with fins projected outward in eight channels. The equipment developed is first model using Unigrafix Nx-8 and steady state thermal analysis of fins is done in Ansys workbench 16.0. A simple, compact, high efficiency, low cost device is developed, also a new technology of heat pipe embedded oil cooler is learnt in this present work. This paper discusses the performance of heat pipe embedded oil cooler in terms of LMTD, overall heat transfer coefficient and effectiveness. Further it discusses the performance evaluation of the straight fin setup.