Water Jacket Research Articles

Comparative Analysis of Surface-Attached Cooling Structure for Efficient Thermal Management of SPMM-TW

Efficient thermal management is the essential precondition for electrical machines to achieve high power density and reliable operation. This paper presents a surface-attached cooling structure (SACS) for the thermal management of slotless permanent magnet motor (SPMM) with toroidal winding. The SACS consists of several channels attached to the surface of the toroidal winding, and the shorter heat path guarantees that the heat generated in the winding can be effectively extracted. Three-dimensional electromagnetic finite-element analysis and the computational fluid dynamics are used to evaluate the losses of the SPMM and obtain the accurate convective heat transfer coefficient (CHTC). For predicting the winding temperature accurately, the layered winding model is proposed to simulate the actual winding conditions. In addition, the influence of different channel materials on temperature rise is experimentally evaluated on the same prototype. The experimental results show that the layered winding model can well simulate and predict the actual temperature distribution of the winding, and the SACS can effectively reduce the temperature rise of the winding compared with the housing water jacket cooling, where the SPMM with the SACS can withstand a continuous current density of 17.2 A/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> and a peak current density of 28 A/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .

Waste heat recovery system for marine engines optimized through a preference learning rank function embedded into a Bayesian optimizer

Waste heat recovery is a proven process to improve efficiency on engines and meets current necessities of the maritime industry. Since January 1, 2023, already built vessels must meet the energy efficiency indicators known as EEXI and CII. Aiming to reduce fuel consumption and mitigate pollution emissions, a novel waste heat recovery system composed of steam Rankine cycle, organic Rankine cycle, thermoelectric harvesters and desalination is presented. High, medium and low-grade waste heat from exhaust gas, jacket water, lubricating oil and engine block radiation are targeted for recovery. Performance assessment of each subsystem when implemented on a real case study 6-cylinder medium speed marine engine is analyzed. The equivalent electricity production concept was used for the assessment of the desalination subsystem. The proposed system effectively recovers waste energy, offering economic benefits, reducing pollution and satisfying the daily demand of fresh water. Also, optimal states of the waste heat recovery are provided via Bayesian optimization, which requires an evaluation function for the system to be optimized. However, this function is not available and cannot be straightforwardly established, since the quality of waste heat recovery depends on some indicators with a trade-off among them. Hence, a preference learning procedure that exploits expert knowledge is proposed to induce a function of this kind from those indicators in order to be embedded into the Bayesian optimization procedure afterward. Applied to the case study engine, a fuel consumption reduction of 15.04% is achieved. Fuel savings lead to an improvement in energy efficiency indicators, achieving a reduction of 6.98% on the EEXI and a 13.85% on the CII.

Modelling hot distortion of inorganic bonded sand cores and application on complex 3D printed automotive cores

Inorganic bonded sand cores are getting increasing attention in industry due to their environmental advantages, and they are now widely used for series production in automotive applications. The advantages of these binder systems are nevertheless associated with a greater sensitivity of the core quality in relation to the manufacturing and storage process before casting, which is also having a major impact on the core strength. This paper presents the current work in integrating the modelling of the binder decomposition and evaporation of binder water with the mechanical performance of partially hardened and dried sand cores. This allows a local description of mechanical properties, considering different behaviour in compression and tension which depends on temperature and different levels of moisture content through the core. Recent work has shown the importance of including creep effects in the numerical modelling of 3D Printed (3DP) inorganic sand cores. Measurements of the mechanical behaviour of 3DP cores compared to shot cores have shown some fundamental differences in strength due to different density and binder content. This has been investigated in detail in collaboration with a major automotive manufacturer and the application of the model extension was done on a complex water jacket core.

Thermal Management Techniques in Metal Hydrides for Hydrogen Storage Applications: A Review

Metal hydrides are a class of materials that can absorb and release large amounts of hydrogen. They have a wide range of potential applications, including their use as a hydrogen storage medium for fuel cells or as a hydrogen release agent for chemical processing. While being a technology that can supersede existing energy storage systems in manifold ways, the use of metal hydrides also faces some challenges that currently hinder their widespread applicability. As the effectiveness of heat transfer across metal hydride systems can have a major impact on their overall efficiency, an affluent description of more efficient heat transfer systems is needed. The literature on the subject has proposed various methods that have been used to improve heat transfer in metal hydride systems over the years, such as optimization of the shape of the reactor vessel, the use of heat exchangers, phase change materials (PCM), nano oxide additives, adding cooling tubes and water jackets, and adding high thermal conductivity additives. This review article provides a comprehensive overview of the latest, state-of-the-art techniques in metal hydride reactor design and heat transfer enhancement methodologies and identifies key areas for future researchers to target. A comprehensive analysis of thermal management techniques is documented, including performance comparisons among various approaches and guidance on selecting appropriate thermal management techniques. For the comparisons, the hydrogen adsorption time relative to the reactor size and to the amount of hydrogen absorbed is studied. This review wishes to examine the various methods that have been used to improve heat transfer in metal hydride systems and thus aims to provide researchers and engineers working in the field of hydrogen storage with valuable insights and a roadmap to guide them to further explore the development of effective thermal management techniques for metal hydrides.

Cooling water jacket design of motorized spindle system using multi-objective topology optimization

The heat dissipation performance is the main factor affecting the dynamic accuracy of the motorized spindle system. Currently, the cooling water jacket with the traditional spiral and serpentine channels is usually used for the heat dissipation of the motorized spindle system. However, the traditional channels of the cooling water jacket cannot meet the increasing demand on its heat dissipation performance, and have the disadvantages of a large flow resistance and uneven cooling temperature. In view of the above challenges, a high-efficiency and strong-convergence structure design method is proposed for the cooling water jacket based on the multi-objective topology optimization to improve the heat dissipation performance and reduce the pressure drop loss. A lightweight conjugate heat transfer equivalent model, which can significantly reduce the computation time and improve the convergence performance, is constructed for the cooling water jacket based on the Darcy model. Then the topology structure of the cooling water jacket is optimized with the equivalent model, and the topology optimization channel is verified by the Reynolds-averaged Navier-Stokes model. The results show that the Darcy equivalent model and the Reynolds-averaged Navier-Stokes model are in a reasonable agreement. Finally, the cooling water jackets with the topology optimization and traditional cooling channels are embedded into the motorized spindle system, and the multi-physical field simulation is conducted for the motorized spindle system to validate the heat dissipation performance of the cooling water jacket. The results indicate that the cooling water jacket with the topology optimization channel has a much more outstanding heat dissipation performance and lower pressure loss than the cooling water jacket with the traditional spiral and serpentine channels. The high-efficiency and strong-convergence structure design method is feasible to get the effective topology structure of the cooling water jacket, and provides a reference for the thermal design of the motorized spindle system.

Organic Rankine cycle turbogenerator cooling – Optimization of the generator water jacket heat exchange surface

Discharge of excess heat from the micro-turbine electric generator is an important issue for the micro-turbine operation and should be considered during the design process. The manuscript is intended to present a new tool for rapid shape optimization of the heat exchanging surface of the ORC (Organic Rankine Cycle) micro-turbine electric generator. The optimization of the water jacket geometry of a 10 kWe ORC micro-turbine generator is performed by making use of a modified, with respect to the models presented in the literature, 0D heat transfer model of the finned heat exchange surface of the cooling water jacket, and a genetic algorithm. As a result of optimization, an apparent reduction in fin size and increased fin density at the finned wall surface is achieved, yielding a significant increase of the heat transfer coefficient and a temperature decrease of the electric generator stator. The temperature at the shell surface tangential to the electric generator stator was found to decrease by over 6°C. A considerable reduction of temperature gradients around the water jacket wall is also reported.The results of optimization from the 0D model are verified by numerical simulation using a full 3D CFD model of fluid flow and conjugate heat transfer (CHT) in Ansys CFX for the original and optimized geometries. The CFD CHT model was first validated using experiment-based correlations for heat transfer in liquid flow over a circular cylinder pipe for a wide range of Reynolds numbers.The obtained temperature decrease in the optimized ORC electric generator stator for the nominal operating point of the ORC generator is found similar for both 0D and 3D models. The temperatures calculated in the 0D model at the shell surface tangential to the electric generator stator deviate from respective CFD values by 0.5–1.5°C. Another operational case beyond the nominal operating point has been analysed making use of the 3D CFD method as well, showing that the optimized geometry is characterized by an improved heat exchange performance not only for the nominal operating point.

Experimental study of the features of filtration of non-Newtonian oils in a porous medium

The current state of development of deposits with high-viscosity oils is characterized by a low value of the achieved oil recovery with a high water cut in the produced wells. However, ways to improve the implemented development systems in order to increase the recovery factor in conditions of high water cut in well production, especially in the late stage of operation requires further research. Therefore, this research intended to investigate features of filtration of non-Newtonian oils in a porous medium. Oil fields with a complex geological structure have been discovered in many oil and gas regions of the world. These fields are characterized by a small oil-saturated thickness of the reservoirs, low reservoir properties, high viscosity of reservoir oil and heterogeneity of productive horizons. To study the filtration process, a specially designed installation was used. Clearly, the main elements are a column (core holder) with a water jacket, an oil tank, a thermostat and a high-pressure air tank (compressor). A research experiment was undertaken in two oil fields, which are X and Y. The results of physicochemical properties of oil field X showed that the density was 0.878g/cm3, followed by sulfur content (1.51%), pitches (21.89), asphaltenes was 4.19, and paraffin was 5.18.

Investigation of Ferrofluid Cooling for High Power Density Permanent Magnet Machines

This article investigates an advanced thermal management method adopting ferrofluid (FF) for improving the end-winding cooling of permanent magnet (PM) machines. An oil-based liquid with nano-sized ferromagnetic particles (which is known as FF) is used to fill in the cavity around the end windings. This is to establish an effective heat flux path between the end winding that is often regarded as hot spot in electrical machines and the external cooling system, i.e., water jacket, to improve the cooling performance of the PM machines. This improvement does not only result from the higher thermal conductivity and thermal expansion of the nanofluid with metal particles but also from strong thermomagnetic convection generated by the magnetic body force of the ferromagnetic particles within the FF. Multiphysics models considering the interaction between the electromagnetic field, the heat transfer, and the fluid dynamics have been built to study the thermal performances of a PM machine under different load conditions. Several factors affecting the thermomagnetic convection, such as the temperature-dependent magnetization curve of the FF, the concentration, and different ferromagnetic materials as well as different current densities, have been investigated to analyze their influences on cooling performance. One major finding is that, compared with other coolant without magnetic body force, the FF can significantly reduce machine peak temperature, e.g., by around <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${36.4}~^{\circ }\text{C}$ </tex-math></inline-formula> when the current density is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\boldsymbol {22.1}~\text {A} / {\text {mm}}^{ \boldsymbol {2}}$ </tex-math></inline-formula> .

Thermodynamic analysis of exhaust heat recovery of marine ice using organic rankine cycle

The use of organic Rankine cycle power systems for waste heat recovery on marine internal combustion engines can help to mitigate the GHG and reduce the fuel consumption of the marine engine. In this paper, the internal combustion engine combined with an organic Rankine cycle system was developed to analyze the performance of waste heat recovery from the exhaust gas of a heavy-duty marine Diesel engine via five selected working fluids with low global warming potential and ozone depletion potential. The net output power and thermal efficiency for each of the selected working fluids were obtained. Results indicate that the working fluids of butane have the best performance among the selected working fluids with the power efficiency of the organic Rankine cycle subsystem of 12.27% under the power load of 100%. For the overall proposed system, the maximum net power output is 1048 kW and the power efficiency is 36.47%. Besides, the total thermal efficiency of the proposed system was 67.94% when considering the recovered waste energy from jacket water.

Review on Thermal Behavior and Cooling Aspects of Axial Flux Permanent Magnet Motors–A Mechanical Approach

With the increasing demand for high-energy density motors for applications such as electric vehicles and aircraft propulsion, axial flux permanent magnet motors are promising. However, utmost care should be taken when designing an axial flux permanent magnet motor with a higher torque density because of thermal effects. To enhance the reliability and overall performance of a motor, efficient thermal management is important, because the torque density is restricted by maximum temperature. Therefore, this study comprehensively reviews different techniques used for the thermal modeling of motors. Computational fluid dynamics, the lumped parameter method, and finite element analysis were used to calculate the total heat transfer inside the motor. Various heat enhancement techniques for an axial flux permanent magnet motor have been presented, including core cooling (water jacket cooling, air cooling, and oil cooling) and winding cooling (direct slot cooling, end winding cooling, and fins). Finally, two case studies of an 8kW AFPM motor and a 65kW AFPM motor with a cooling arrangement are discussed.

DESIGN OF HOUSEHOLD ANAEROBIC BIO-DIGESTER FOR BIOGAS PRODUCTION FROM ABATTOIR WASTE

Despite the awareness on the importance of using biogas produced from various biomasses that were previously considered as wastes, the fact remains that its applicability or usage in domestic purposes such as cooking stoves has not really gained attention especially in developing countries. Based on this reason, this research designed a batch system biogas generating facility that will serve the energy needed for cooking meals by a family size of six members, using rumen contents of cattle (Bos indicus) as biomass. The results made known that an anaerobic digester having a capacity of 2.7m 3 will perfectly serve for such facility to meet its intended use when fed with 72kg of substrate per batch, while the gas holder volume should be 0.527m 3. Necessary appurtenances including water jacket were designed and detailed dimensions, drawings as well as costing of the entire facility were provided to ease fabrication and possibly adjustment in the future if the need arise.

RETRACTED ARTICLE: Detailed study of efficient water jacket cooling system for induction motor drive used in electric vehicle

RETRACTED ARTICLE: Detailed study of efficient water jacket cooling system for induction motor drive used in electric vehicle

Winding Embedded Liquid Cooling for Slotless Motors in Transportation Applications

A novel winding embedded liquid cooling (WELC) concept is presented to improve the thermal management of slotless motors for transportation applications. The concept introduces liquid cooling channels through the non-magnetic thermal plastic winding support in a slotless motor to reduce the thermal resistance between the heat source and the sink. This article demonstrates the efficacy of the WELC concept for a 11.5-kW slotless motor using computational fluid dynamics (CFD). A lumped parameter thermal network has also been developed for the WELC concept, which has been validated using the CFD analysis. The simulation results of WELC concept have been experimentally validated for an 11.5-kW slotless motor. It is shown that the WELC concept can achieve a continuous current density of 19.0 A(rms)/mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{2}$</tex-math></inline-formula> for an allowable temperature rise of 80 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{\circ }$</tex-math></inline-formula> C; the achieved continuous current density is 35% higher than that of a conventional axial in-slot water jacket cooling. The short time (18 s) peak current density achieved with the WELC concept is 39.8 A(rms)/mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{2}$</tex-math></inline-formula> .

Optimalisasi Perawatan Sistem Auxiliary Boiler Dalam Menghasilkan Uap Panas

Auxiliary boilers that have the function of producing hot steam are auxiliary steam boilers. The function of this steam is to heat the fresh water jacket cooling and fuel, drive the turbine pump, heat the liquid in the tank and room. This study aims to optimize the maintenance of auxiliary boiler systems, especially in the auxiliary steam boilers. This research was conducted in the engine room on the MT ship. This research is a qualitative descriptive study with data collection obtained from observation, interviews and documentation. The result of this study is the implementation of maintenance of auxiliary boiler components including: Boiler water; main burner; pilot burner; blower; and pumps. Overall, the average before optimizing maintenance, the effectiveness of the implementation of the planning maintenance system in auxiliary boilers was around 58.86%, and the average increased by 27.57% so that the average after optimization of maintenance with the guidelines for planning system maintenance became 86.43%. Auxiliary boiler system maintenance steam boiler In MT Tender Harmony can run optimally so that it can produce quality steam so that it can heat the fuel optimally.

A Study on Additive Manufacturing of Metal Components for Mobility in the Area of After-Sales with Spare and Performance Parts

Mobility is undergoing changes. Increasingly strict legislation regarding pollutant emissions and the protection of the environment are more important than ever. The change to electric mobility is also presenting the mobile world with new challenges and opportunities. Vehicles are becoming more and more efficient with higher power densities and better performance. Application-adapted components are being developed and used as a matter of preference. New production technologies can help to realise the change in mobility reliably. Additive manufacturing is one way of producing functionally integrated and performance-optimised components. AM offers the possibility to produce application-specific performance parts. Electric vehicles often have a problem with the thermal load of the components during power output and charging. Additively manufactured components with optimised topology and integrated cooling strive to achieve higher power density, enhanced cooling performance, and improved mechanical properties. AM not only makes it possible to produce functionally integrated and application-adapted components but also to reduce CO2 emissions and conserve resources. The potential of additive manufacturing for mobility is particularly interesting for the spare and performance parts sector. Components can be improved in performance and manufactured directly on-site. The higher power density and the elimination of transport routes can make an additional significant contribution to environmental protection. This paper presents an overview of the current state of additive manufacturing in the field of electromobility with regard to replacement and performance parts using 3D metal printing. Based on an extensive literature research, a market overview is given. This serves as the basis for the further procedure and, building on this, the advantages of additive manufacturing are demonstrated using the example of an electric motor. The selected electric motor is an example of a defective component in a vehicle that needs to be replaced and whose performance can be improved by additive manufacturing and which can be produced on-site in a quantity of one. The motor is verified by means of a FEM simulation in order to determine the selection of an optimal water jacket topology and to demonstrate further potential for the future.

Cooling System Design and Thermal Analysis of Modular Stator Hybrid Excitation Synchronous Motor

Hybrid excitation synchronous motor has the advantages of uniform and adjustable electromagnetic field, wide speed range and high power density. It has broad application prospects in new energy electric vehicles, wind power generation and other fields. This paper introduces the basic structure of hybrid excitation motor with modular stator, and analyzes the operation principle of hybrid excitation motor. The cooling structure of the water-cooled plate is designed, and the effects of the thickness of the water-cooled plate and the number of water channels in the water-cooled plate on the heat dissipation capacity of the water-cooled plate are analyzed by theoretical and computational fluid dynamics methods. The effects of different water cooling plate structures on water velocity, pressure drop, water pump power consumption and heat dissipation capacity were compared and analyzed. The influence of different inlet flow velocity on the maximum temperature rise of each part of the motor is analyzed, and the temperature of each part of the motor under the optimal water flow is analyzed. The influence of the traditional spiral water jacket cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of the motor components is compared and analyzed. The results show that the water-cooled plate cooling structure is more suitable for the modular stator motor studied in this paper. Based on the water-cooled plate cooling structure, the air-water composite cooling structure is designed, and the effects of the air-water composite cooling structure and the water-cooled plate cooling structure on the maximum temperature rise of each component of the motor are compared and analyzed. The results show that the maximum temperature rise of each component of the motor is reduced under the air-water composite cooling structure.

Experimental study of saving energy and improving Stirling water dispenser performance using the waste heat of both pistons friction

Water dispensers are considered essential. So, water dispensers that use vapor-compression urgently need more energy-saving and environmentally friendly alternatives. Stirling water dispensers are a suitable option. However, the waste heat generated via friction between the pistons and their cylinders decreases the cooling load and power consumption. The present work uses the waste heat of both piston friction via water jackets to save energy and improve Stirling water dispenser performance. The result indicates that the heating and cooling loads of the present water dispenser are increased by about 2952 W and 834 W using the waste heat of both pistons at 1200 rpm. The increase of water flow rate within water jackets increases the heating and cooling loads due to the increased absorption of frictional heat. The comparison shows that the current water dispenser reveals an average increase in cooling load of up to 400 percent at low speeds and 61 percent at high speeds, and an increase in heating load of up to 390 percent at low speeds and 28 percent at high speeds.

CFD modelling on flow field characteristics of engine cooling water jacket and its cooling performance improvement based on coolant transport path analysis method

Reasonable coolant flow distribution and its heat transfer coefficient (HTC) distribution are of great significance to the cooling performance of water-cooled engine. Therefore, the present paper proposes a coolant transport path analysis method aiming at analyzing coolant velocity distribution and optimizing the coolant flow characteristics of water jacket based on Computational Fluid Dynamics (CFD), with particular emphasis on the assessment of coolant flow velocity distributions of high-temperature area of engine head water jacket. First, the coolant flow characteristics of a single-cylinder water jacket is investigated and it is found that coolant velocity of exhaust bridge is less than 1.5 m/s and the HTC distribution of water jacket under three flow conditions of 15 L/min, 25 L/min and 35 L/min have a small area reaching 5000 W/(m2∙K). Some areas have no coolant flow and the mass flowrate distribution of each gasket hole is unreasonable, proving that original water jacket structure has some shortcomings and need to be optimized. Based on coolant transport analysis, an improved design of the single cylinder water jacket is proposed and HTC distribution of improved water jacket meet cooling requirements that HTC in high heat load area are above 5000 W/(m2∙K). The coolant transport path analysis method for optimizing coolant flow characteristics of water jacket proves to be an effective way through successful application and remarkable achievement in the other single-cylinder water jacket and two-cylinder water jacket that coolant flow distribution become more reasonable and coolant velocity of high-temperature areas are bigger than 1.5 m/s.

Experimental study on the heat transfer characteristics of separate heat pipes

ABSTRACT In this paper, two special-shaped separated heat pipes with different condensation section structures are designed. The working medium is water, and the filling rate is 65%. The evaporation section is placed in the hot water tank, and the condensation section is equipped with a cold water jacket. The effects of different structures of condensing section on the thermal performance of separated heat pipes are experimentally studied, and the temperature changes of the two separated heat pipes during start-up and stable operation under different heating power are analyzed. The results show that the heat transfer characteristics of the two separated heat pipes are different due to the different structures of the condensation section, and the heat transfer capacity of sample 2 is higher. At the same time, the temperature fluctuation in the condensing section of sample 2 is also quite different from that in the condensing section of sample 1, and the temperature fluctuation in the condensing section of sample 2 is greater. The wall temperature fluctuates periodically in a steady-state, and a fast Fourier transform is used to analyze the temperature fluctuation.

Life cycle analysis of a waste heat recovery for marine engines Organic Rankine Cycle

The Marine ORC prototype unit is based on a conventional low-temperature subcritical Organic Rankine Cycle and has been designed as a waste heat recovery system for the jacket water of marine diesel auxiliary internal combustion engines (ICEs). In the present work, the key remarks of the life cycle analysis on the experimental test rig, installed in Athens, Greece, are presented. The analysis of the impacts has been conducted using the ReCiPe 2016 method. The system was evaluated in coupling with the auxiliary ICE and was compared against an ICE of the same electrical energy output on annual basis. The ICE-marine ORC system enhanced the environmental performance up to 3% on many impact categories, apart from the mineral resources and the terrestrial ecotoxicity which is related to the extended use of copper-based materials. The working fluid was found to have a major impact on the ozone depletion and the global warming categories with a share of 95.9% and 91.6% over the total equivalent system emissions, respectively. On the other hand, the replacement of R134a with R1234ze was found to reduce the ORC's global warming impact down to less than 10% of its initial value.