High Specific Heat Research Articles

Research of Heat Transfer Characteristics of Supercritical CO2 in Spiral Tube Heat Exchangers

The spiral tube heat exchanger has the advantages of stable structure, high space utilization rate, and strong heat transfer ability. Supercritical carbon dioxide (s-CO2) has the advantages of high thermal conductivity, high specific heat capacity, and low viscosity. When the spiral tube heat exchanger uses supercritical carbon dioxide as the heat transfer medium, the two complement each other’s advantages and can further improve the heat transfer efficiency and optimize the space utilization rate. However, under the coupling influence of factors such as centrifugal force and buoyancy force, the heat transfer process of s-CO2 in the spiral tube is extremely complex. At present, there is no design criterion or empirical correlation with strong universality in the industrial field. Based on this, this paper mainly uses ANSYS FLUENT, a numerical simulation software suitable for numerical simulation, to study the influence of internal vortex field and secondary flow intensity on the thickness of thermal boundary layers through a combination of numerical simulation and theoretical analysis. At the same time, by changing various operating and structural parameters, the heat transfer characteristics of supercritical s-CO2 in the spiral tube heat exchanger are analyzed and summarized. In addition, we also established a new buoyancy factor, Fu, and tested that when Fu < 1.6 × 10−5, the effect of the buoyancy lift in the pipeline disappeared. At the same time, a correlation formula for predicting the heat transfer performance of spiral tube heat exchangers with a Nu number error less than 20% is established in this paper, which can provide solid theoretical guidance for industrial application.

Three-Dimensional Air Quality Monitoring and Simulation of Campus Microenvironment Based on UAV Platform

This study innovatively employs drones equipped with air quality sensors to collect three-dimensional air quality data in a campus microenvironment. Data are accurately corrected using a BP neural network, and a cubic model is constructed using three-dimensional interpolation. Combining photogrammetry technology, this study analyzes air quality patterns, finding significant differences from macro trends. Construction activities and large electronic experimental equipment significantly increase PM2.5 levels in the air. In rainy weather, the respiration of vegetation is enhanced, leading to higher CO2 concentrations, while water bodies exhibit higher temperatures in rainy weather due to their high specific heat capacity. This research not only provides a new perspective for microenvironment air quality monitoring but also offers a scientific basis for future air quality monitoring and management.

An Untethered Soft-Swallowing Robot with Enhanced Heat Resistance, Damage Tolerance, and Impact Mitigation

Soft robotics focuses on addressing the locomotion problem in unstructured environments and the manipulation problem of non-cooperative objects, which inevitably leads to soft robots encountering multiple uncertainties and damages. Therefore, improving the robustness of soft robots in hostile environmental conditions has always been a challenge. Existing methods usually improve this robustness through damage isolation, material elasticity, and self-healing mechanisms. In contrast to existing methods, this paper proposes a method to improve the robustness of an untethered soft-swallowing robot based on the physical properties of fluids, such as the high specific heat capacity of water, the viscosity of soft glue, and the shear thickening of non-Newtonian fluids. Based on this method, we developed a soft-swallowing robot with enhanced heat resistance, damage tolerance, and impact mitigation capability by only replacing its fluid working medium. Experiments show that the developed soft-swallowing robot can withstand high temperatures above 600 °C, maintain high performance even after enduring hundreds of damages, and protect grasped object from more than 90% of external impacts. This principle extends beyond the three fluids used in this study. Other fluids, such as magnetic fluid, can increase adhesion to metal materials, whereas oily fluids can reduce frictional resistance between soft structures. Additionally, other solid materials with elasticity and compliance can serve as alternative working mediums for the soft-swallowing robot. This work contributes an effective method for fluid-dependent soft robotic systems to resist the damage from uncertain factors in harsh environments.

Combinatorial approach to predict synergistic ablation behavior of carbon fiber phenolic composites under aerodynamic loading

The study conducts a comprehensive analysis across 1-D, 2-D, and 2-D axisymmetric geometries, investigating temperature profiles, surface recession patterns, pyrolysis gas flow dynamics, and density fluctuations within the composite material. The findings highlight the effectiveness of the FEA technique in modeling complex multi-physical interactions associated with ablation phenomena. The carbon-phenolic composites, characterized by low thermal conductivity, high specific heat capacity, and substantial char yield, are shown to be particularly well-suited as ablative materials. The char layer formed during ablation acts as an additional insulating barrier, enhancing thermal protection. In a specific case study, a 2 cm thick composite laminate was subjected to an intense heat flux of 200 W/cm2 for 180 s. The results demonstrate that the Thermal Protection System (TPS) effectively maintains the back face temperature below 350 K for the initial 60 s under uniform heat flux conditions. However, beyond this period, the back face temperature gradually increases, reaching 1698 K at the end of the 180-s simulation. These insights into the material’s thermal performance under severe heat exposure conditions provide valuable guidance for applications requiring effective heat management and thermal protection.

Study and design of a Hydrogen liquefaction process using ethane as refrigerant fluid

Hydrogen liquefaction is an essential process in cryogenics, facilitating the efficient storage and transport of hydrogen as a clean energy carrier. This study investigates the liquefaction of hydrogen at a flow rate of 100 kmol/h, with an energy consumption of 447.05 kW. The process relies on sophisticated equipment, including multi-stage compressors and expansion devices, which play key roles in cooling and compressing the hydrogen gas. One of the notable advantages of this system is the energy recovery achieved by an expansion device, which generates 262.1 kW, enhancing overall efficiency.The hydrogen compression stages use a multi-stage compressor that employs water as the primary coolant. With a flow rate of 389.4 kmol/h, water is chosen due to its high specific heat capacity and availability, making it an ideal coolant for this cryogenic process. Ethane, serving as a secondary refrigerant, operates at a flow rate of 32 kmol/h. Its non-corrosive and inert properties contribute to system durability, while a portion of the ethane is strategically recycled through heat exchangers to minimize consumption and optimize cooling efficiency. Hydrogen enters the system at 5×10⁵ Pa and 288 K, and is gradually cooled and compressed to 2×10⁵ Pa and 22.75 K, resulting in the final liquid hydrogen product. This significant temperature reduction, achieved through the combined cooling effects of water and ethane, is critical for the successful liquefaction of hydrogen. The optimized use of refrigerants and efficient energy recovery in the expansion stages reduce operational costs and enhance process sustainability.

Effect of Morphology and Concentration of CeO2 Nanoceria on the Thermal Stability of Polyvinyl Alcohol Films

Objective: To determine the thermal stability of polyvinyl alcohol films under different concentrations of CeO2 nanoceria. Method: Cerium Oxide doped polyvinyl alcohol (PVA) nano-composites were synthesized by the traditional solution casting method for various concentrations of nano CeO2 by solution combustion method. The thermal properties of prepared PVA-2.5 wt% CeO2, PVA-7.5 wt% CeO2 , PVA-12.5 wt% CeO2, and PVA-25 wt% CeO2 composite films were elucidated by using techniques such as Differential Scanning Calorimetry, Thermogravimetry analysis and Differential Thermal analysis. Findings: The glass transition temperature of the pure PVA is found to be 114°C, whereas it varies between 110°C-120°C for composite films. The melting temperature of the composite films is the same as that of pure PVA except in the case of 7.5wt% CeO2 and 25wt% CeO2 composites. The reduced melting point of these composites elicits a decrease in crystallinity. A 12.5 wt % and 25 wt% CeO2-PVA nano-composite films exhibit an increase in the final degradation temperature, a high specific heat capacity, low mass loss, and a larger residual weight, indicating their potential applicability in thermal coating and thermal sensing applications. Polyvinyl alcohol (PVA) films are being used routinely as a dielectric layer for electrical applications due to the good physiochemical and dialectic properties of the material. An incorporation of CeO2 nanoceria improves not only the thermal but also the mechanical properties of PVA and extends its application for electrical and optical operation. Here in the present study, different concentrations of CeO2 were incorporated with the PVA and analysed for the thermal properties. The study showed that 12.5 wt % and 25 wt% CeO2-PVA nano-composite enhanced PVA film thermal stability. Keywords: PVA-CeO2 Nanocomposites; Differential Scanning Calorimetry; Thermogravimetry Analysis and Differential Thermal Analysis; Physical properties and thermal properties

Experimental investigations on strength and microstructural characteristics of air-cell impregnated light weight concrete

Concrete structures have high massive building materials than steel structures and possess very low thermal conductivity and high specific heat capacity. However, an efficient approach to reducing high production cost and structural weight of concrete elements without impacting their strength evolve as a growing necessity that leads to innovation in the Light weight concrete (LWC) fields such as aerated concrete and foamed concrete. Those large bubbles seem highly likely to get a break, move upwards through buoyancy and may get lost, while concrete has been mixed, transported, placed and vibrated. Hence to prevent increased bubble spacing, and air loss and to increase concrete durability, a sort of micron-sized air-cells could be generated in aerosol form, by passing out compressed air to dense form generating surfactants. Therefore to circumvent certain drawbacks of conventional LWC, the study delineated to bring out an innovative air-cell impregnated concrete (AIC) material, with homogenous mixing of cement, sand, water and uniformly distributed micron-sized air-cells wherein course-aggregates were replaced with air-cells. This uniform air-cell distribution creates durable concrete with unique feature characteristics since the micron-sized air-cells will be stable and does not collapse. The suitable surfactant towards contributing the strength and durability of proposed AIC structure are assessed, based on results.

Experimental and comparative analysis between nitrile rubber foam insulated and vacuum insulated fiber reinforced plastic tank used in a low temperature sensible heat storage system for building space cooling applications

AbstractThermal energy storage devices are gaining importance and momentum in the building space cooling and renewable energy applications. Retaining the stored energy for long hours through proper insulation is crucial in achieving economic benefits. In the present research, a novel composite material (FRP) is introduced for the development of cool storage tank along with two different methods of insulation (nitrile rubber foam insulation and vacuum insulation) to assess the performance of cool energy retention. The results show that the effect of vacuum insulation is lower compared with nitrile rubber foam insulation. This is due to the low specific heat capacity of the FRP material compared with air that increases the surface temperature of the tank than the ambient air during the day time in the case of vacuum insulation. Hence the study concludes that the additional layer of insulation material with high specific heat capacity than the ambient air to be added on the surface to avoid the overheating of the wall surface. The results are useful in designing the insulation for thermal storage tanks and managing the heat loss.

Growth, optical and thermal properties of YbxSm1-xCa4O(BO3)3 crystals

YbxSm1-xCOB (x = 0.1, 0.2) crystals were grown by the Bridgman method for the first time. The purpose of this paper is to evaluate the application prospect of Yb:SmCOB crystal in quasi-parametric chirped pulse amplification (QPCPA) and frequency-doubling laser. The phase structure, thermal properties and optical properties of Yb:SmCOB were studied, and the density of states of SmCOB crystal was calculated by first-principles. The effective segregation coefficient Keff of Yb0.1Sm0.9COB and Yb0.2Sm0.8COB crystals are 0.89 and 0.88, respectively. The thermal diffusivity and thermal conductivity of Yb:SmCOB decrease with increasing temperature. The specific heat increases with the increase of temperature and eventually tends to be constant. The specific heat of Yb:SmCOB crystal is greater than 0.70 J/(g·K) at room temperature. The transmittance of Yb:SmCOB crystal reaches 87 % in the range of 500 ∼ 900 nm. With the increase of Yb3+ doping concentration, the UV absorption cut-off edge is red shifted. The frequency doubling emission peak of Yb:SmCOB crystal at 490 nm was measured by 980 nm laser. Yb:SmCOB has the characteristics of high transmittance and high specific heat, and has application potential in laser frequency doubling and QPCPA.

DFT study of the brownmillerite-type strontium-based oxygen-deficient perovskites SrTMO2.5 (TM = Mn, Fe, Co and Cu)

DFT studies are performed to investigate the crystal structure and geometry, electronic and magnetic properties of brownmillerite-type strontium-based oxygen-deficient perovskites [Formula: see text] (TM = Mn, Fe, Co and Cu) in orthorhombic phase. The comparison of the calculated lattice parameters shows consistency with the experiments, and all these perovskites are thermodynamically stable as revealed by cohesive energy. The spin-dependent calculations of the electronic band profiles demonstrate the metallic behavior of all these deficient perovskites. The increase in electrical resistivity and electronic thermal conductivities with temperature also confirms the metallic behavior of these compounds. The optimized ground state energies in different magnetic phases and post-DFT treatment confirm that [Formula: see text] and [Formula: see text] are stable in C-type AFM, [Formula: see text] is in G-type AFM and [Formula: see text] in A-type AFM phase, respectively. The high specific heat of these deficient perovskites makes them good candidates for high-temperature technology. Based on the above physical properties, it is expected that these deficient perovskites are potential candidates for spintronics and magnetic storage devices.

A numerical investigation on heat transfer characteristics of a particle cluster in fluid with variable properties

This work investigates the heat transfer characteristics of particle clusters under the effects of the complex properties of supercritical water (SCW). It analyzes the heat transfer characteristics of sub-particles and the average heat transfer characteristics of particle clusters. The results reveal a phenomenon of shifting positions of high specific heat regions. It led to variations in the dimensionless heat transfer coefficient distribution. Furthermore, the results indicate that as the heat transfer process strengthens, the effects of variations in property distribution on heat transfer tends to stabilize. Based on this conclusion, the effects of variations in property distribution on heat transfer are categorized into Stable Effects Region and Non-Stable Effects Region. By utilizing the principles of fluid flow-heat transfer coupling and similarity, a heat transfer prediction model for particle clusters in SCW is established.

Synergistic performance enhancement of lead-acid battery packs at low- and high-temperature conditions using flexible phase change material sheets

Thermal management of lead-acid batteries includes heat dissipation at high-temperature conditions (similar to other batteries) and thermal insulation at low-temperature conditions due to significant performance deterioration. To address this trader-off, this work proposes a thermal management solution based on flexible phase change materials (PCMs) with moderate thermal conductivity and other favourable properties including high specific heat capacity and high latent heat. A novel type of flexible PCM sheets is prepared with paraffin, olefin block copolymers (OBC) and expanded graphite using the co-melting method. The flexible PCM sheets are attached to a common type of lead-acid battery packs (12 Ah, dimensions of 151 × 98 × 97 mm) and thermal management performance is experimentally investigated at –10 °C and 40 °C as low- and high-temperature conditions, respectively, along with 25 °C as a baseline case for comparison purposes. Thermal properties of the battery packs such as temperature regulation and electric properties including charge/discharge capacities and rates are studied synchronously based on a standard high-performance battery detection facility. The results indicate that at –10 °C condition, the PCM sheet enhances thermal insulation of the battery pack and significantly promotes the service temperature during the charging processes. Compared with a benchmark pack attached with an encapsulated sheet, the charge and discharge capacities of the PCM-attached pack are improved by 3.7% and 5.9%, respectively. At 40 °C condition, phase transition of the PCM sheet restrains the temperature rise of the battery pack, with a maximum temperature decrease of 4.2 °C during the charging processes relative to the benchmark pack, and the temperature of the PCM-attached pack is maintained below 45 °C across 60% of the overall charge period. The overcharge and overdischarge have also been alleviated by 3.2% and 2.8%, respectively, and thus the running stability and service lifespan can be improved. The proposed PCM sheets with preferable thermal properties demonstrate potential to promote performance of lead-acid battery packs and such components are also expected to improve heat dissipation and thermal insulation in similar applications including building energy saving, thermal management of electronic chips and thermal regulation of electronic devices.

Experimental investigation of humidified air condensation in different rows of serpantine heat exchanger – Cooling water flow rate effect

Condensing economizers are used in the industry as they enable the acquisition of additional heat during vapor condensation. In condensing heat exchangers, water is the usual cooling agent due to its high specific heat capacity and thus efficient heat removal. Therefore, experiments of hot humid air condensation in a serpentine economizer being cooled by water were performed to reveal the effect the cooling water flow rate has on humidified air condensation in separate rows of the serpentine type economizer (with vertical tubes). The results have shown that the cooling ratio (mass flow ratio between the coolant and the humid air) had a minor effect on the distribution of the humidified air temperature along test section for inlet Reynolds number of 3000–10000. The effects on the condensation flux distribution in different rows were much stronger. The most optimal cooling ratio was determined to be 3. The results have shown that the biggest condensation efficiency is up to 35%. It was revealed that in some cases the convection was prevailing in the first rows of the economizer and this resulted in a decreased efficiency/performance of the exchanger.The obtained results from the practical point of view will provide an extended basis for the optimisation of the design of economizers for waste heat recovery in the cases of different cooling water flow rates. It could also be applied to validate computational models developed for condensation heat transfer and condensate flux numerical modelling along economizer.

Growth, spectroscopic, thermal and laser frequency doubling properties of CTGAS crystal

A novel nonlinear optical crystal Ca3Ta(Ga0.7Al0.3)3Si2O14 (CTGAS) was successfully grown by the Czochralski method. The structural, spectroscopic and thermal properties have been systematically investigated, and the laser frequency doubling process has also been explored. Excellent thermal properties have been presented, such as moderate thermal conductivity, high specific heat, and low thermal expansion anisotropy. The electronic structure and optical properties have been investigated using the XPS technique and simultaneous assisted first-principles calculations. The optimal phase matching in type I (40.45°, 30.0°) and type II (64.73°, 0°) orientations were determined, frequency-doubling output was achieved in type I and type II, with laser energies of up to 10.04 mJ and 10.14 mJ obtained @ 532 nm, and optical-to-optical conversion efficiencies of 14.04 % and 17.21 %, respectively. The experimental findings demonstrate the great potential of CTGAS crystal as a frequency-doubling material.

Investigating thermal runaway propagation characteristics and configuration optimization of the hybrid lithium-ion battery packs

Thermal runaway (TR) and its propagation (TRP) in lithium-ion batteries are critical safety concerns. The emergence of hybrid battery packs, combining different battery types (referred to as AB batteries), has gained significant attention as a potential solution to enhance battery safety. However, there is a lack of evaluation regarding the TRP characteristics of these configurations. In this study, various AB battery configurations, incorporating NCM 811 and LFP batteries, are examined through simulations and experiments to investigate their TRP behavior. The findings reveal that: (1) A well-designed AB battery configuration can effectively suppress TR, achieving a balance between high energy density and safety. The high TR trigger temperature and specific heat capacity of LFP batteries play a vital role in impeding TRP. (2) The 8L8L battery configuration successfully suppresses TRP, while the 88L88 configuration requires the addition of heat-insulating sheets for effective TRP suppression. (3) Increasing the number of LFP batteries proves to be an effective approach in preventing TRP. For instance, configurations such as 88LL88 and 888888LL888888 demonstrate no occurrence of TRP. The study concludes by summarizing the TRP characteristics of different AB battery configurations, offering valuable insights for the design of high-safety battery packs.

Experimental study on knock suppression by direct water injection and direct ammonia-water injection based on low-flow injector under high load

Under the appropriate injection strategies, both direct water injection and direct ammonia-water injection can effectively suppress the knock, but the effect of the knock suppression is slightly different. In this paper, water and ammonia-water were respectively injected directly into the cylinder of a high performance port gasoline injection engine by modified low-flow direct injectors. The effects of direct injection timing and injection ratio on knock, combustion and emission were investigated. Both water and ammonia-water can effectively suppress knock in SI mode. Compared to water, ammonia-water exhibits a more prominent inhibitory effect on knock at lower DI ratios. However, when the ratio was further increased, the difference between the effects of ammonia-water and water on the inhibition of knockdown became less pronounced. Water and ammonia-water DI affect the knock through different mechanisms due to their unique chemical properties. While water predominantly influences the later combustion phases due to its rapid vaporization and high specific heat capacity. Ammonia-water primarily impacts the early combustion phase because of its complex combustion process and lower laminar flame speed.

Heat Transfer Performance Studies of Packed Bed Distillation Setup

Heat transfer performance studies done in a setup involving a stirred tank reactor and packed bed distillation column. Stirred tank reactor consists of double pitch blade impeller with rotational speeds varied from 40-120 rpm. The water-air system was taken into consideration. The reactor is jacketed with Therminol 55 as a heating medium. Therminol 55 is used as a heating medium because of its higher specific heat and boiling point. Column comprises of 3 packed bed segments, each of 1m in height and jacketed with Therminol 55. Therminol 55 is used as a source of indirect heating to negate any heat losses in the column. The column is randomly packed with Mellapak250Y packing. The data collected by experiments especially characterizes the packed bed distillation setup and heat transfer performance. The work evaluates effect of agitation on overall heat transfer coefficient and mass flow/ boil up rate calculated theoretically and experimentally. Use of efficient correlations along with various necessary dimensionless numbers and rudimentary parameters were clubbed to form a MATLAB model useful for verification of theoretical data. The comparison of theoretical and experimental overall heat transfer coefficient and mass flow/boil up rate is done. The study done on the setup used shows conclusions regarding overall heat transfer coefficient and mass flow/boil up rate with respect to agitator speed and Reynolds number. The theoretical calculated values of overall heat transfer coefficient and mass flow/boil up rate are compared with the experimental ones and conclusions taken out regarding the reactor and column contribution. Finally, the Reynolds number and mass flow/boil up rate relation is shown

Experimental and numerical study of a novel composite building wall U-value

The present study aims to minimize the overall heat transfer coefficient (U-value) and heat flux through building walls to improve indoor thermal comfort, using different bricks and insulating materials in building wall construction. The building walls of three different types of bricks (Type-1, Type-2, and Type-3) were tested to compare the U-value through the wall. The brick with the low U-value was used to build a composite wall with the addition of glass wool and air cavity. The experiment was conducted maintaining different hot chamber temperatures (40℃ to 65℃) to see the effect of hot chamber temperature on the U-value. The temperature of the cold fluid chamber is increased by 0.9℃ in 0 to 210 min of testing duration. The maximum heat flux using Type-3 brick in the composite wall is reduced by 3.37%, and the percentage reduction in indoor temperature is 40.83%. Steady-state numerical analysis was also performed to perceive the temperature distribution on the composite wall surface and found to be well-matched with the experimental model with a percentage deviation of 1.96%. The results suggested that using glass wool and air cavities with low thermal conductivity, low density, and high specific heat capacity effectively reduces the U-value throughout the building wall.

Observing and identifying fouled ballast bed: On-site testing with infrared thermography (IRT) and uncovering thermodynamic transfer mechanisms within the ballast bed

The ballast bed serves as the foundation of the ballasted track, and its performance is maintained through periodic ballast cleaning. Early detection of fouled ballast bed significantly reduces maintenance workload and capital investment. Some scholars have studied the feasibility of utilizing infrared thermography (IRT) for detecting fouled ballast bed (DBF) and have made some progress. Existing studies have predominantly employed simulated boxes to simulate the ballast bed. To better reflect real-world conditions, this study established two sections of ballast bed on a newly constructed line: one with clean ballast and the other fouled, with a volumetric fouling rate (VFR) of 27.6 % (FI ≈ 21.5 %). Moreover, this paper takes a pivotal step in exploring the thermodynamic transfer mechanisms within the ballast bed, the influences of meteorological factors on the detection effectiveness of IRT, and other detection indicators that could be used for DBF.The results demonstrate that the different void fractions and composition substances of the clean and fouled ballast beds (CFB) contribute to their distinct thermodynamic properties. Furthermore, the high specific heat capacity of water exacerbates the thermodynamic property difference between the CFB. In terms of meteorological factors, both the solar radiation intensity (S) and air temperature (T) have a significant positive impact on the temperature of the ballasted structure (STT) and the temperature difference between the CFB (CF-S). Throughout the day, as the S and T increase, the ballast bed surface absorbs more solar heat than it loses, leading to an increase in its surface temperature. When it exceeds the soil temperature (S-S), heat is transferred downward. Since the poor heat conduction of the clean ballast bed, it has a higher surface temperature. As the S and T decrease, heat convection and conduction become dominant, leading to a decrease in the surface temperature of the ballast bed (BT-S). When the BT-S is lower than the S-S, heat is transferred upward, causing the surface temperature of the fouled ballast bed (F-S) to potentially exceed that of the clean ballast bed (C-S). Furthermore, the humidity (H) has a strong negative impact on the STT, while on sunny days following rain, it has a significantly positive impact on the CF-S. The effects of wind speed (W) on the STT and the CF-S are not prominently observed due to its low values during the experiment. Without considering rainfall, higher S and T, combined with reduced W, result in a greater CF-S and are more conducive to advancing fouling detection. Hence, the CF-S can reach up to about 3 °C on a sunny day and may even rise to about 5 °C after rainfall. Nonetheless, the CF-S is only around 0.71 °C on a cloudy day and 0.25 °C at night. Unexpectedly, there is a significant temperature difference between the sleeper and the ballast bed or the steel rail. These indicators could potentially be used for DBF on cloudy days. Overall, these findings demonstrate the feasibility of using IRT for DBF in the field, provding a broader theoretical support for its advancement and implementation.

Prediction of geothermal temperature field by multi-attribute neural network

Hot dry rock (HDR) resources are gaining increasing attention as a significant renewable resource due to their low carbon footprint and stable nature. When assessing the potential of a conventional geothermal resource, a temperature field distribution is a crucial factor. However, the available geostatistical and numerical simulations methods are often influenced by data coverage and human factors. In this study, the Convolution Block Attention Module (CBAM) and Bottleneck Architecture were integrated into UNet (CBAM-B-UNet) for simulating the geothermal temperature field. The proposed CBAM-B-UNet takes in a geological model containing parameters such as density, thermal conductivity, and specific heat capacity as input, and it simulates the temperature field by dynamically blending these multiple parameters through the neural network. The bottleneck architectures and CBAM can reduce the computational cost while ensuring accuracy in the simulation. The CBAM-B-UNet was trained using thousands of geological models with various real structures and their corresponding temperature fields. The method’s applicability was verified by employing a complex geological model of hot dry rock. In the final analysis, the simulated temperature field results are compared with the theoretical steady-state crustal ground temperature model of Gonghe Basin. The results indicated a small error between them, further validating the method's superiority. During the temperature field simulation, the thermal evolution law of a symmetrical cooling front formed by low thermal conductivity and high specific heat capacity in the center of the fault zone and on both sides of granite was revealed. The temperature gradually decreases from the center towards the edges.