Ceramic Heat Research Articles

Performance optimization of the transient thermoelectric cooling for the temperature control of the chip working under dynamic power

The thermoelectric cooler (TEC) operating under the transient mode showed a stronger short term cooling effect than that of the steady state mode. In this study, a chip cooling experimental setup with the chip modeled by a ceramic heater was constructed using a commercial Bi2Te3-based TEC. A transient three-dimensional numerical model was established for the system optimization. The impacts of the pulse voltage amplitude, pulse voltage trigger time, pulse voltage time span, and the power magnitude of the chip on the peak temperature of the chip were analyzed in detail. The results showed that the experimental and numerical simulations were in high agreement with an error of only 3.6 %. When a pulse voltage of 12 V was applied to the TEC, the experimental results showed that the peak temperature of the chip with a pulse power of 48 W was reduced by 15.3 °C, while the simulation results demonstrated a reduction of 15.6 °C. The increase in the pulse voltage width and the pulse thermal power resulted in a larger temperature reduction. The transient cooling effect of the TEC presented a promising solution for temperature regulation in modern chips operating under dynamic power conditions.

Energy-efficient rapid additive manufacturing of complex geometry ceramics

Energy-intensive industries are one of the key greenhouse gas emitters, and decarbonization of such industries is a top priority to promote global sustainability. As one of the top energy-intensive industries, ceramic manufacturing industries are urged to boost energy efficiency in ceramic structure production. In this paper, we present a rapid and low carbon footprint strategy for freeform manufacturing spatial ceramic composites. Our approach integrates layer-by-layer deposition, photothermal in-situ solidification, and self-sustaining ceramization, enabling consolidation using only 1920 J energy. Compared to state-of-the-art processes, energy consumption can be reduced by over 100-fold, resulting in an estimated 1000-fold decrease in CO2 emissions. This energy-efficient process also demonstrates the rapid fabrication of ceramic gyroid heat exchangers, capable of withstanding extreme environments.

Methodology of a thermal injection mold design with locally applied heating coatings on the cavity wall

AbstractThe thermal balance of injection molds is defined by the cooling channel layout. However, the fluid tempering of injection molds underlies certain restrictions concerning the thermal dynamic and the local limitation of the zone of influence. The optimal heat balance within the mold to minimize warpage cannot be solely achieved with conformal cooling channels. Ceramic heating coating systems applied by Thermal Spraying on the cavity wall are a novel tempering method for high heating rates and offer the possibility of a more local heat input. In terms of the thermal mold design, the position and size of local heating coating systems need to be determined. A methodology is proposed, which connects the optimization of part warpage by defining the necessary local heat flux within the mold with the determination of the heating coating placement. Due to the dependence of the coating placement on the heating time and the power, different decision criteria of these parameters are discussed with regard to the process efficiency. The developed methodology can calculate the necessary heating power distribution to homogenize the surface temperature and freeze time. A second step discretizes the heating power distribution to certain manufacturable heating zones.

Heat Transfer of an Integrated Counterflow Ceramic Heat Exchanger

The ceramic-based heat exchanger is one of the leading contenders for high-efficiency concentrating solar power plants using a molten salt heat transfer fluid and a supercritical carbon dioxide Brayton power cycle operating at temperatures above 700 °C due to the excellent resistance of ceramics to corrosion, oxidation, erosion, creep, and fouling. In the present study, the thermal performance of a ceramic silicon carbide prototype heat exchanger, with semi-elliptical heat transfer channels, integrated header channels, and a counterflow configuration fabricated by using binder jetting additive manufacturing, was experimentally investigated. Experimental heat transfer tests of the prototype were conducted at high temperatures and under various test fluid flow rates and inlet temperatures. The experimental heat transfer rates compared favorably with simulation predictions.

Additive manufacturing of ceramic multi-material heating and ignition elements for a sustainable space access

The continuous advancement in the space industry and in space access has opened the doors to greater global participation and exploration, with numerous nations, institutes and companies now actively engaged in space exploration. This expansion owes much to the progress in commercial space technologies, such as reusable launch vehicles and micro satellites, which have significantly reduced the overall costs associated with space missions, thereby enhancing space accessibility.Nevertheless, to foster further growth, it is necessary to look at further options of making space access more sustainable and cost-effective. For that, it is important to investigate and identify the cost drivers. An example is the use of traditional manufacturing techniques and materials, which come with inherent limitations, notably in terms of design flexibility and performance efficiency. This results in solutions that are not only time-consuming to manufacture but also not the most effective, making it a costly process.To address these challenges, increasing emphasis is being placed on utilising alternative manufacturing methods, such as additive manufacturing technologies combined with high-performance ceramic materials. This aims to reduce the overall number of manufacturing steps for producing a component and to optimise complex and functional parts reducing the overall costs of mass-produced or individually manufactured components, as evident in current studies.The primary objective of this study is to enhance space accessibility through the development, production and optimisation of electrically functional, all-ceramic and multi-material components (heating/ignition elements). For that, the AM technology “CerAM MMJ” in combination with high performance ceramic material are utilised and discussed. Subsequently, these components undergo electrical measurements and tests, and the resulting data is presented and analysed in the following sections.The findings aim to shed light on the current state of the art and whether the additively manufactured, fully ceramic and electrically functional components could represent a more cost-effective alternative to conventionally manufactured components in the future.

Piezoelectric-pneumatic material jetting printing for non-contact conformal fabrication of high-temperature thick-film sensors

Conformal printing of high-temperature thick-film sensors (TFSs) on intricate surfaces is crucial for precise integration and enhanced functionality. However, traditional contact printing faces challenges in terms of the complex motion control of 3D surfaces. With the core concept of non-contact printing, this study employs piezoelectric-pneumatic material jetting (PPMJ) to achieve rapid and uniform manufacturing of complex and multi-material conformal TFSs. PPMJ enables a wide viscosity range (50–100,000 mPa.s) and high solid content (60 wt%), accommodating various types of inks, from insulating to semiconductor materials to high-temperature alloy slurries, thus providing a broad operational window for shape control and performance modulation in the conformal manufacturing of TFSs on curved surfaces. Microscale shape control of ceramic ink features, including a parallel three-phase contact line, uniform print dimensions, and post-curing shape control, was systematically investigated. PPMJ printing facilitates the successful in situ fabrication of multi-layer TFSs, featuring the self-assembly of droplets and dependable printing consistency, with nozzle-to-substrate heights ranging from 1 to 10 mm, thus advancing the structural arrangement, design, and manufacturing of conformal multi-layer TFSs on curved surfaces. For example, the polymer-derived ceramic heat flux sensor printed by PPMJ demonstrates repeatable high-temperature responsiveness and can be integrated on the surface of turbine blades, withstanding thermal impacts from flames exceeding 800 °C. Hence, PPMJ printing technology opens new possibilities for the conformal manufacturing of various sensors on complex 3D surfaces.

Investigation of Heat Exchanger Performance in The Heating Tank Section of Loop FASSIP 03 NT

The Passive System Simulation Facility (FASSIP) loop is an experimental test facility for a passive cooling system to recover the residual heat from decay produced by the reactor core during accident conditions. The Heating Tank Section (HTS) is one of the components of the FASSIP 03 NT facility. This component is equipped with a heat exchanger, 3 types of heat exchangers can be applied to HTS. Namely heat exchangers of the Straight Pipe Heat Exchanger (SPHE) type, the Straight Pipe Fins Heat Exchanger (SPFHE) type, and the Helical Pipe Heat Exchanger (HPHE) type. A modification was made to increase the efficiency of HTS, namely replacing the electric heater on the HTS from a ceramic band heater type to an immersion heater type. With this modification, it is necessary to know the performance of the heat exchanger on HTS and its speed in reaching operational temperature. The HPHE-type heat exchanger is more efficient than the SPHE-type and SPFHE-type heat exchangers. The HPHE-type heat exchanger has a much larger length of 5.5 m, so the thermal resistance (Rth) is very small, namely 0.003926 ℃/W. To reach the working fluid temperature in the range of 50 – 90 ℃, the HPHE-type heat exchanger requires 35 – 86 minutes.

Improving the tracking and erosion resistance of silicone rubber using Fe2O3 and platinum catalyst

AbstractIn typical HTV silicone rubber for composite insulators subjected to a 4.5 kV inclined plane (IP) test, alumina trihydrate loading exceeds 40 wt%, which limits the rubber content and weakens the antiaging properties. This study compares two methods for enhancing tracking and erosion resistance while reducing ATH content to meet IP test requirements. Increasing Fe2O3 content from 1.5 wt% to 3 wt% promotes the formation of mullite. The formed ceramic layer isolates heat and oxygen and hence facilitates the specimen to pass the IP tests with less content of ATH. By contrast, Pt/NS system cannot suppress the tracking efficiently by forming the SiOC ceramics at high ATH loading. The decomposition of ATH will generate water vapor and lead to holes in the surface. Both moisture and oxygen absorbed have a detrimental effect on the suppression mechanism of the Pt/NS system. Consequently, it is recommended that the content of Fe2O3 can be increased slightly to lower the ATH content in the traditional HTV SiR formula used for the composite insulator. Besides, when the content of ATH is relatively high, the use of the Pt/NS system is not recommended.

Study on the Cooling Performance of a Focused Ultrasonic Radiator for Electrical Heating Elements.

In this work, a focused ultrasonic radiator is proposed for cooling the electrical heating elements in the focal region, and its working characteristics are investigated. The analyses of the FEM computational and flow field visualization test results indicate that focused ultrasound can generate forced convective heat transfer by the acoustic streaming in the focal region, which can cool the heating elements effectively. Experiments show that when the input voltage is 30Vp-p and the ambient temperature is 25 °C, the focused ultrasonic radiator can cause the surface temperature of the heating element (high-temperature alumina ceramic heating plate with a diameter of 5 mm) in the focal region to drop from 100 °C to about 55 °C. When the diameter of the electrical heating element is changed from 5 mm to 30 mm, the cooling effect is similar in the focal region. Compared with a fan, the focused ultrasound radiator has a shorter cooling time and a more concentrated cooling area. The focused ultrasonic radiator proposed in this work is suitable for some special environments.

К ОПРЕДЕЛЕНИЮ МОЩНОСТИ НАГРЕВАТЕЛЯ АППАРАТА ДЛЯ ИСКУССТВЕННОГО ОСЕМЕНЕНИЯ КОРОВ

Existing devices for cows insemination’s visocervical method do not have a tool for this device’s working part heating. This discomfort for animals in the cold season creating, their insemination’s success reducing. Therefore, an apparatus with a heated working part is proposed. This device’s working part requiring temperature by a heater located in this device working part tube’s middle is maintained. This device’s heater uniform tube heating must ensure along its entire length and maintain the tube set temperature within 37-39°C at an outdoor temperature of 2°C and an uneven surface of ±3°C heating. To assess the heaters’ number effect on the tube heating uniformity, a device working part’a mockup sample with various options for the ceramic heaters’ arrangement was tested: 1 heater in the tube’s center, 2 heaters at equal distances along the tube’s length and 3 heaters evenly along the tube length distributing. This heating degree and its distribution along the tube length were recorded by Dannai thermal imager using. This situation was also simulated by the APM WinMachine’s software product using. The required heater’s power from the tube based on the criterion equations’ heat losses was calculated, and also was determined by APM WinMachine using. Modeling by the APM WinMachine package and a field experiment using showed that by this device working part’s uniform heating ensuring, the heater must be either linear or consist of three heaters evenly along the tube distributing. The required heater’s power in WinMachine calculated was 5,20 W, and by criterion equations’ using - 7,72 W, that calculation results’ sufficient convergence for both methods indicating.

Highly oriented BN-based TIMs with high through-plane thermal conductivity and low compression modulus.

In the pursuit of effective thermal management for electronic devices, it is crucial to develop insulation thermal interface materials (TIMs) that exhibit exceptional through-plane thermal conductivity, low thermal resistance, and minimal compression modulus. Boron nitride (BN), given its outstanding thermal conduction and insulation properties, has garnered significant attention as a potential material for this purpose. However, previously reported BN-based composites have consistently demonstrated through-plane thermal conductivity below 10 W m-1 K-1 and high compression modulus, whilst also presenting challenges in terms of mass production. In this study, low molecular weight polydimethylsiloxane (PDMS) and large-size BN were utilized as the foundational materials. Utilizing a rolling-curing integrated apparatus, we successfully accomplished the continuous preparation of large-sized, high-adhesion BN films. Subsequent implementation of stacking, cold pressing, and vertical cutting techniques enabled the attainment of a remarkable BN-based TIM, characterized by an unprecedented through-plane thermal conductivity of up to 12.11 W m-1 K-1, remarkably low compression modulus (55 kPa), and total effective thermal resistance (0.16 °C in2 W-1, 50 Psi). During the TIMs performance evaluation, our TIMs demonstrated superior heat dissipation capabilities compared with commercial TIMs. At a heating power density of 40 W cm-2, the steady-state temperature of the ceramic heating element was found to be 7 °C lower than that of the commercial TIMs. This pioneering feat not only contributes valuable technical insights for the development of high-performance insulating TIMs but also establishes a solid foundation for widespread implementation in thermal management applications across a range of electronic devices.

Design and development of an artificial incubator

This paper presents the design and development of an artificial incubator for poultry eggs. The incubator is designed to maintain the optimal temperature and humidity conditions for embryo development, and it is also equipped with an egg-turning mechanism. It was designed using Solid Edge software, and it was constructed using plywood, ceramic bar heaters, electric fans, ballcock valves, egg turning steel mechanism, and a CO2 meter. The temperature and humidity conditions inside the incubator were maintained within the desired ranges, and the egg-turning mechanism worked effectively. The results of this study show that this artificial incubator could be a reliable and effective tool for hatching poultry eggs. The incubator is easy to use and maintain, and it is affordable for local poultry farmers. Future studies should focus on determining the conditions under which the incubator will yield the best results in terms of hatching efficiency.

An Experimental Apparatus for Bench-Scale Fire Testing Using Electrical Heating Pads

This research study concerns an experimental, budget-friendly, electricity-powered apparatus for bench-scale fire testing. The apparatus consists of various elements, of which the most important are ceramic heating pads, used to impose heat fluxes on exposed surfaces of specimens. The test method allows to control the heating pads’ temperature and to adjust the distance between the heating pads and the specimen to obtain well-defined heat fluxes up to 50–60 kW/m2. Higher heat fluxes and temperatures can be obtained by setting the heating pads in full power mode, with or without the use of a thermal shield, which can lead to heat fluxes up to 150 kW/m2. The heating and thermal boundary conditions imposed by the apparatus are characterised and discussed, and the thickness of the convective boundary layer at the heating pads’ surface is estimated significantly lower than in the case of gas-fired radiant panels. The performance of the apparatus is analysed for various conditions: controlling the temperature of the heating pads, in an open environment or with the presence of thermal shields, and in full power mode. A few examples of application of the apparatus to fire test typical construction materials (steel and glass) are also presented. These results emphasise the well-defined heating conditions in temperature-controlled mode. The study finally discusses the advantages and limitations of the apparatus, as well as many possibilities of future applications and improvement for future research studies.

Foamy ceramic filters and new possibilities of their applications

Peculiarities of sintering of foamy ceramic filters based on submicron aluminum oxide powders with additions of titanium oxide and manganese dioxide nanopowders are considered. The processes of removal of polymeric and binder paraffin material during sintering have been studied. The physical and mechanical properties of the obtained porous permeable filters with a foamy structure were analyzed in details. At a sintering temperature in an air atmosphere of 1350 °C, sufficiently high physical and mechanical properties were obtained, which made it possible to use the developed filters as catalyst carriers for vehicle exhaust gases. Bench comparative tests have shown that ceramic filters with a foamed structure are promising catalysts for afterburning car exhaust gases instead of ceramic honeycomb blocks of catalyst carriers. The developed technology allows reducing the sintering temperature of porous foam ceramic filters to 1350 °C and replacing expensive high-temperature ceramic heaters with cheaper nickel-chromium ones.

Development of Functionally Graded Metal-Ceramic Systems by Directed Energy Deposition: A Review

Ceramics and metals are the two vastly explored classes of materials whose individual characteristics and targeted applications differ significantly. Continuous thrust for space exploration and energy generation demands materials with a wide range of properties. To tackle this demand, ceramic-metal combined structures that club heat, wear, and corrosion resistance of ceramics to the high toughness, good strength, and better machinability of metals are desirable. While various processing routes to combine ceramics and metals have been developed through the years, solutions to address problems associated with the interface, thermal property mismatch, and poor adhesion need to be explored. In this context, Functional Graded Materials (FGMs) have attracted particular attention by virtue of their ability to avoid sharp interfaces and local stress concentrations. Out of all, Additive Manufacturing (AM) routes, particularly the Directed Energy Deposition (DED) technique, is emerging as a productive technique capable of fabricating a wide range of metal-ceramic graded structures. This paper specifically discusses metal-ceramic FGMs ́ capability as a potential high-temperature material with customized multifunctional material properties. It further outlines the primary concerns with the realization of metal-ceramic graded structures and major techniques developed to mitigate problems encountered in processing them. Specific emphasis is laid on the powder-based Laser DED (L-DED) technique of FGM fabrication owing to its control over complex geometries and microstructural engineering.

Heterogeneous oxidation of different atomic clusters in amorphous SiBCN ceramic associated with phase separation

In this study, the microstructure of amorphous SiBCN ceramic derived from polyborosilazane and the crystalline SiBCN ceramic heat treated at 1600 ℃ was investigated and their oxidation behavior and kinetics involving different atomic clusters or phases during the non-isothermal oxidation process up to 1500 ℃ were analyzed to obtain their different micro mechanisms. Due to higher oxidation activity, the atomic clusters in amorphous structure can be oxidized at lower temperatures and exhibit lower activation energy than the crystal phases in crystalline structure, but have much higher oxidation resistance due to the phase separation-coupled heterogeneous oxidation of different atomic clusters.

Fabrication and capillary performance of multi-scale microgroove ceramic wicks via nanosecond laser irradiation for ultrathin ceramic heat pipes

Ultrathin ceramic heat pipes have great potential in solving the heat dissipation problems for power semiconductor devices with ever-increasing power density. Ceramic wick structures with superior capillary performance plays a decisive role in the heat transfer performance of the ceramic heat pipe. In the study, a multi-scale microgroove wick (MSMGW) prepared by laser irradiation is developed. The effects of laser scan pitch, laser fabrication parameters and ceramic material on the surface morphology, wettability and capillary performance of the MSMGW were investigated. The 66 μm thick ceramic wick proposed that consists of micron-sized microgrooves, nanoscale voids and material surface reconsolidation layers demonstrates remarkable capillary performance. The laser scan pitch, laser power, repetition frequency, and scanning speed have significant impacts on the surface morphology and capillary performance of MSMGW. The MSMGW with optimal parameters could reach capillary wicking height of 114 mm within 28 s and yield a capillary parameter (K/reff) of 1.49 μm. Moreover, MSMGW on the material of alumina with advantages of excellent machining property and technology maturity, and working fluid of DI water with high vaporization latent heat and wide operating temperature range, exhibits the maximum capillary performance, indicating its highly promising prospects for high-performance ultrathin ceramic heat pipes.

Coatings to Prevent Oxidation and Erosion of Carbon–Carbon and Carbon–Ceramic Heat Shields

Coatings to Prevent Oxidation and Erosion of Carbon–Carbon and Carbon–Ceramic Heat Shields

A comparison of induction heating and ceramic pads for localised post-weld heat treatment of friction taper hydro-pillar welds in thick-walled steam pipe

The WeldCore® friction taper hydro-pillar (FTHP) welding platform provides integrated coring of 8 mm diameter creep condition monitoring specimens and automated welding of the hole in thick-walled steam pipe. The FTHP welds should be restored as closely as possible to their original material condition, and are therefore given a post-weld heat treatment (PWHT) that is usually done using flexible ceramic heating pads wrapped around the pipe. However, it may often be more desirable to perform localised induction heating using a ‘pancake style’ coil placed only directly at the weld location. This approach to localised induction heating is not a qualified procedure for thick-walled pipe and there is a scarcity of published literature on this topic. Hence this paper compares flexible ceramic pads and induction techniques for PWHT of FTHP welds in A106 Gr B pipe, 406 mm in diameter and with 20.4 mm wall thickness. The comparison considers metallography, microhardness, tensile and U-bend tests and concludes that both techniques are equally good in PWHT.

Additive Manufacturing of Liquid-Cooled Ceramic Heat Sinks: An Experimental and Numerical Study

With recent advances in power electronic packaging technologies, liquid-cooled ceramic heat sinks have been considered as a promising solution for further improving the performance of power electronic devices. In this study, several aluminum oxide heat sinks were fabricated and tested using the digital light processing-based additive manufacturing method, to verify their practical performance. The results showed that the complex cooling structures inside the heat sinks can be completely formed and exhibited high surface quality. The experimental thermal and hydraulic performances of the heat sinks were consistent with the numerically modeled predictions. Furthermore, by exploiting the advantages of additive manufacturing, a direct manifold microchannel (MMC) configuration was designed to reduce the vertical flow of the traditional MMC configuration and achieve an improved cooling efficiency. At a constant volumetric flow rate of 1 L/min, the direct MMC configuration achieved a 19.8% reduction in pressure drop and an 11.8% reduction in thermal resistance, as well as a more uniform temperature distribution.