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Journal of Thermal Science
Journal Prestige (SJR): 0.316  Citation Impact (citeScore): 1 Number of Followers: 21  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1993-033X - ISSN (Online) 1003-2169 Published by Springer-Verlag  [2468 journals]
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- A Self-Calibrating Digital Twin Approach by Integrating CFD and Sensor
Data for Coal-Fired Boiler Water Wall Temperature-
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Abstract: Digital twin is a cutting-edge technology in the energy industry, capable of predicting real-time operation data for equipment performance monitoring and operational optimization. However, methods for calibrating and fusing digital twin prediction with limited in-situ measured data are still lacking, especially for equipment involving complicated multiphase flow and chemical reactions like coal-fired boilers. In this work, using coal-fired boiler water wall temperature monitoring as an example, we propose a digital twin approach that reconstructs the water wall temperature distribution with high spatial resolution in real time and calibrates the reconstruction using in-situ water wall temperature data. The digital twin is established using the gappy proper orthogonal decomposition (POD) reduced-order model by fusing CFD solutions and measured data. The reconstruction accuracy of the digital twin was initially validated. And then, the minimum number of measured data sampling points required for precise reconstruction was investigated. An improved uniform data collection method was subsequently developed. After that, the computational time required for the digital twin and the traditional CFD was compared. Finally, the reconstruction method was further validated by in-situ measured temperature from the in-service boiler. Results indicate that the established digital twin can precisely reconstruct the water wall temperature in real time. Thirty-nine sampling points are sufficient to reconstruct the temperature distribution with the original data collection method. The proposed uniform data collection method further reduces the mean relative errors to less than 0.4% across four test cases, and with the constrained technique, the errors decrease to 0.374% and 0.345% for Cases 1 and 3, which had poor reconstructions using the original sampling point arrangement. In addition, the reconstruction time of the digital twin is also considerably reduced compared to CFD. Engineering application indicates that the reconstructed temperatures are highly consistent with in-situ measured data. The established water wall temperature digital twin is beneficial for water wall tube overheating detection and operation optimization.
PubDate: 2025-04-15
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- Effects of SiO2 and MgO on the Thermophysical and Mechanical Properties of
Al/Al2O3 Composites and Their Compatibility with Al-Si Alloys-
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Abstract: Al/Al2O3 is crucial encapsulation composites used in solar thermal storage systems. Al/Al2O3 composites with varying SiO2 and MgO contents were prepared using Al powder and Al2O3 powder as raw materials, with SiO2 and MgO as sintering aids, through a cold-press sintering method. The latent heat, thermal conductivity, and bending strength of the composites were measured. The microstructure of the composites and their compatibility with Al-Si (88%−12% in weight) alloy were observed and analyzed. The relationship between thermal properties, mechanical properties, compatibility, and microstructure was investigated. The results show that as the SiO2 content increases and the MgO content decreases, the comprehensive performance of the composites first improves and then decreases. The composites exhibit the best comprehensive performance when the mass contents of SiO2 and MgO are both 1%, with a bending strength of 79.645 MPa, thermal conductivity of 23.903 W/(m·K), and a latent heat of 93.61 J/g. In the compatibility experiment, as the number of thermal cycles increases, the diffusion distance of Si atoms in the composite first increases and then stabilizes, maintaining a distance of approximately 150 μm, indicating good compatibility.
PubDate: 2025-04-15
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- Experimental Investigation of the Flame Propagation Speeds of Ammonia/Air
and Ammonia/Hydrogen/Air Mixtures at Elevated Temperatures-
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Abstract: Flame propagation speeds are reported for ammonia/hydrogen/air mixtures with equivalence ratios in the range of 0.5–1.5, preheated gas temperatures ranging from 298 to 673 K and hydrogen volume fractions of 0%, 20%, and 50%. The measurements were conducted using a Bunsen burner and an optical schlieren system. The results show that the flame propagation speed and combustion stabilities of the premixed gases increase with increasing preheating temperature. The combustion stability is significantly improved under the 20% hydrogen volume fraction condition. For the NH3/H2 mixtures with a hydrogen volume fraction of 50%, the flame propagation speed at 673 K with a stoichiometric ratio is approximately 4.85 times that at 298 K. The experimental results show that at 673 K, the flame propagation speed of the NH3/H2/air mixture increases by 7.8 times when the hydrogen volume fraction increases from 20% to 80%. The numerical results predicted with the Mei, Shrestha, and Stagni mechanisms are compared with the experimental data. The mechanisms proposed by Shrestha and Stagni overestimate the flame propagation speed, especially at high preheating temperatures. The results predicted with the Mei mechanism are consistent with the available data. The concentrations of OH, H, O and NH2 are increased by the hydrogen addition; thus, the ammonia consumption is accelerated.
PubDate: 2025-04-12
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- Experimental Investigation on High-Temperature Condensation Heat Transfer
and Flow Characteristics of Organic Fluid Used in Heat Pump-
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Abstract: Advancements in high-temperature heat pump technology are pivotal for achieving global carbon neutrality goals, with the working fluid’s heat transfer and flow properties being crucial for efficient condenser design. Nevertheless, research on high-temperature condensation of organic fluids is sparse, necessitating the development of accurate correlations for heat transfer and flow characteristics. This study emphasizes experimental research on R245fa’s condensation heat transfer and pressure drop within a 40°C–110°C saturation temperature range inside a plain tube with a 9-mm internal diameter. Sensitivity analysis highlighted the differences in condensation characteristics between high and low temperatures, and influencing mechanisms are revealed. Then, the measured data are employed to assess the accuracy of previous correlations. Based on the importance factor analysis result, adjustments are made to Reynolds number and flow regime boundaries. Finally, the correlations incorporating high temperature condensation of R245fa are developed, yielding a decrease in deviation from 17.6% to 7.23% for heat transfer and from 15.1% to 7.51% for frictional pressure drop gradient. Utilizing the newly developed models, 877 data points across 14 working fluids are predicted, results in a decrease in deviation from 18.85% to 10.65% for heat transfer coefficient, indicating a significant improvement in both accuracy and generality of the developed correlations.
PubDate: 2025-04-12
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- Experimental and Numerical Investigation on Cooling and Aerodynamic
Performance of Turbine Blade Ribbed Squealer Tip-
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Abstract: As one of the hottest components of gas turbine, the blade tip is difficult to be cooled down for the complexity flow field in the tight tip clearance. The blade tip protection requires advanced tip structures. To develop new structures, the effect of ribs on blade squealer tip aerothermal performance and cooling performance were investigated. Ribbed squealers tips (1R, 2R and 3R, compared to the Basic case) were designed and their cooling ability under five coolant blowing ratios (M) were measured by the Pressure Sensitive Paint (PSP) technique, taking film cooling effectiveness (η) as the criterion. Numerical method was validated and then was adopted to analyze the flow field and aerodynamic loss in the tip gap. The results indicated that the cooling coverage and η increase with M for sufficient coolant supply. Compared to the Basic case, the η on the middle section is higher while that on the trailing part is lower for the ribbed squealer tips. The flow field analysis showed that the coolant flows downstream to the trailing edge in the Basic case, bringing additional cooling protect to the downstream region. The ribs induce vortices behind them to involve the local and upstream coolant and prevent upstream coolant from flowing down, leading to the improvement in the local and the degradation in the downstream for the film cooling performance. The aerodynamic results pointed out that the ribbed squealer tips are superior to the Basic case in terms of the aerodynamic performance, even though the tip leakage mass flow of these cases are larger than that of the Basic case. The maximum reduction on pressure loss coefficient is 16.2% for the ribbed squealer tip.
PubDate: 2025-04-11
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- Dynamic Response Characteristics of Multi-Generation System Integrated
with Gas and Heat Storage-
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Abstract: In this paper, a new multi-generation system, incorporating solid oxide fuel cell (SOFC), gas turbine (GT), lithium bromide chiller, gas and heat storage components is proposed to address the issues of volatility in user load and energy source input and mismatching between supply and demand. The dynamic model and control strategy of the system are established, and the system dynamic characteristics in response to solar DNI and external load disturbances are studied. The system can rapidly adjust the key output and input parameters to realize a new supply-demand balance in a shorter period of time by multiple PID control methods. The response processes of two combined cooling, heating and power (CCHP) systems with and without gas storage to cope with load changes are compared. The results show that the CCHP system with gas storage can effectively shorten the response time of load following. The solar collector and the SOFC-GT can reach a new equilibrium within a few tens of seconds under the controller. The response time of the methanol reactor is longer compared to those of solar collector and the SOFC-GT, taking several minutes to stabilize. When the cooling and heating load change, the system can adjust the output to the demand value within 500 and 260 seconds.
PubDate: 2025-04-11
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- Experimental Study on Heat Transfer Characteristics of Supercritical CO2
under Natural Circulation Loop-
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Abstract: The heat transfer characteristics of supercritical carbon dioxide (SCO2) based on natural circulation loop (NCL) are investigated experimentally. A comprehensive analysis is conducted on the impact of single-factor variations in inlet temperature, heat flux, operating pressure, and mass flux on the heat transfer characteristics of SCO2. The results indicate that heat transfer deterioration (HTD) more easily occurs when the inlet temperature exceeds the pseudo-critical temperature. Moreover, the peak of deterioration shifts upstream in the heated section with the increase of heat flux. The inner wall temperature rises with an increase in operating pressure, while it falls with the increase of mass flux. Through an exhaustive analysis of the buoyancy parameter Bo*, it is deduced that buoyancy effect exerts a pivotal influence on the heat transfer process. An improved buoyancy parameter Bo*adv is proposed, enabling precise anticipation of variations in heat transfer coefficients under both normal and deteriorated heat transfer scenarios. Based on experimental data, a novel heat transfer correlation suitable for SCO2 heat transfer in natural circulation is proposed. This new correlation exhibits a more satisfactory predictive accuracy compared to previous correlations; 98.31% and 76.58% of the new correlation predictions under normal heat transfer (NHT) and HTD are within ±20% error range. The research results have significant guiding implications for theoretical research and prediction correlation of HTD phenomenon. This establishes the theoretical groundwork for the implementation of SCO2 natural circulation in Fourth Generation Nuclear Reactors.
PubDate: 2025-04-05
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- Influence of Crosswind on Evaporation Mass Transfer and Heat Exchange in
High-Level Water-Collecting Natural-Draft Wet Cooling Towers-
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Abstract: High-level water-collecting natural-draft wet cooling towers (HNDWCTs) are commonly employed in super-large thermal and nuclear power units. However, research on the effects of crosswinds is still in the exploratory stage. This paper focuses on the fill packing zone and investigates the influence of various crosswind speeds (ranging from 1 m/s to 18 m/s) on convective and evaporation heat transfer processes in the cooling tower. The results indicate that evaporation heat transfer contributes 90% of the total, asserting a predominant role in the thermal performance of the cooling towers. Therefore, this study examines the impact of crosswinds on evaporation mass transfer in HNDWCTs. It has been observed that the “self-reflux” in high humidity region under low wind speeds is the root cause of generating low mass transfer driving force region. As wind speed exceeds 9 m/s, the “high-humidity reflux” transitions to “low-humidity reflux”, which makes the local mass transfer driving force rise back up, and helps to promote the evaporation mass transfer process. This transition mitigates the negative impact of crosswinds, resulting in the stabilization of the evaporation mass transfer and heat exchange reduction at approximately 60%.
PubDate: 2025-04-05
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- A Review on Analytical Heat Transfer in Functionally Graded Materials,
Part II: Non-Fourier Heat Conduction-
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Abstract: Non-Fourier heat conduction models are extended in response to heat transfer phenomena that cannot be accurately described by Fourier’s Law of heat conduction. This paper provides a review of heat conduction in functionally graded materials (FGMs) employing non-Fourier models. FGMs are designed materials with a gradual transition in composition, microstructure, or thermal conductivity throughout their volume. The spatial variation in thermal conductivity can lead to deviations from Fourier’s Law, resulting in non-Fourier heat conduction behavior in certain situations, such as at very short time scales or in materials with high thermal conductivity gradients. Researchers utilized various models, such as, Cattaneo-Vernotte, parabolic two-step model, hyperbolic two-step, phonon kinetic, dual-phase lag, and three-phase lag models to describe non-Fourier heat conduction phenomena. The objective of this review is to enhance the understanding of non-Fourier heat transfer in FGMs. As a result, the analytical studies conducted in this particular area receive a greater emphasis and focus. Various factors affecting non-Fourier heat conduction in FGMs including gradient function, material gradient index, initial conditions, boundary conditions, and type of non-Fourier model are investigated in various geometries. The literature reviews reveal that a significant portion of research efforts is centered around the utilization of dual phase lag and hyperbolic models in the field of non-Fourier heat conduction within FGMs.
PubDate: 2025-04-04
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- Experimental Study on Two-Stage Modification, Combustion and NO
x Emission
Characteristics of Pulverized Coal in a Purification-Combustion Reaction
System-
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Abstract: To achieve deep NOx control, we investigated a purification-combustion system consisting of devolatilizer, swirl burner and down-fired combustor, and explored the influences of primary and secondary air ratios (λp and λ2) on two-stage modification, combustion and NOx emission of pulverized coal in a 30 kW purification-combustion experimental bench. In devolatilizer and swirl burner, the temperature in different positions increases with λp and λ2 rising. Moreover, the location of main burning zone in swirl burner could be changed by increasing λp rather than λ2. CO and H2 are the main burnable components in modified gases, and their concentrations decrease with λp and λ2 increasing. By contrast, the CH4 concentration is extremely low. Purification system composed of devolatilizer and swirl burner outperformed single-stage devolatilizer in increasing specific surface area, pore volume, pore diameter and fuel conversion rate of pulverized coal as well as improving its carbon microcrystalline structure, and these indexes of modified char are better and better with λp and λ2 increasing properly in this system. In down-fired combustor, as λp and λ2 increase, the temperature changes slightly in reduction region, while it decreases in complete combustion region only at lower λ2. Properly rising λp and λ2 will reduce the NOx emission with high efficiency of above 99.00%, but the emission reduction driven by λ2 is limited.
PubDate: 2025-04-04
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- A Review on Analytical Heat Transfer in Functionally Graded Materials,
Part I: Fourier Heat Conduction-
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Abstract: Fourier heat conduction in functionally graded materials (FGMs) has attracted considerable scientific interest due to its simplicity in modeling. FGMs, characterized by a gradual variation in material composition and properties, exhibit unique thermal conductivity behaviors that differ from conventional homogeneous materials. Understanding and analyzing heat transfer in FGMs is crucial for optimizing their thermal performance in various applications. The analytical analysis of Fourier heat conduction in FGMs has facilitated a more profound understanding of the heat transfer phenomena that occur within these advanced materials. This paper provides a comprehensive overview of the research conducted on Fourier heat conduction in FGMs, highlighting the key methodologies, findings, and implications. The literature review showed that the thermal conductivity in FGMs varies spatially, affecting the temperature distribution and heat flux within the material. The gradual variation in material properties in FGMs necessitates the development of specialized analytical solutions to accurately describe the heat transfer behavior. Additionally, the choice of appropriate analytical functions has been found to significantly impact the accuracy and efficiency of the analytical solutions. Researchers have explored various functions, including power functions, exponential functions, and polynomial functions, to represent the temperature distribution within FGMs. It has been observed that the choice of these functions should be based on compatibility with the analytical solution of the heat conduction equation, ensuring accurate predictions of temperature profiles and heat transfer rates.
PubDate: 2025-04-04
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- Comparative Studies on Gas and Spray Flame Structures by LES
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Abstract: To compare structures of turbulent gas and spray flames is helpful for understanding the effect of evaporating droplets on turbulence and turbulent combustion. Presently some investigators did studies on the effect of turbulence on droplet evaporation and the effect of droplet combustion on turbulence, and most of studies paid attention to the time-averaged results. In this paper, the specific feature is to give a review for comparative studies on instantaneous structures of turbulent methane-air jet gas flame, ethanol jet spray flame, methane-air swirling gas flame and heptane-air swirling spray flame by large-eddy simulation (LES) using a second-order moment (SOM) combustion model. The results show that evaporating droplets enhance turbulence and turbulent combustion.
PubDate: 2025-04-02
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- Technical-Economic Analysis and Optimization of Maisotsenko GT-ORC under
Intercooling-
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Abstract: The Maisotsenko gas turbine cycle (MGTC), integrated with a combined aftercooling and regenerative saturator, has the potential to challenge traditional wet air turbine cycles. However, its large water consumption limits its applicability. By integrating an intercooler and Organic Rankine Cycle (ORC) into the MGTC, this study proposes a comprehensive design of IMGT-ORC, which can adjust the water capacity of the saturator, and utilize the sensible heat of cooling water and the latent heat of evaporation in exhaust gas to achieve water and energy saving. Firstly, a sensitivity analysis was conducted to investigate the effects of various parameter variations on thermodynamic and economic indicators under different temperature drop ratios. Subsequently, a multi-objective optimization approach was employed to seek for an optimal balance between economic and environmental benefits. The results showed that either the intercooler or ORC integration can improve the thermal efficiency of the system. In the case of joint setting, the thermal efficiency is relatively increased by 6.89% and the water consumption is relatively reduced by 89.07%. Moreover, although high temperature drop ratio reduces the output of ORC, it enhances the energy efficiency of the top cycle. In terms of cost control, ORC integration may increase the levelized cost of electricity (LCOE) slightly, while the intercooler integration helps offset the increase. Finally, the optimization results show that using the optimal parameter combination can reduce the annual equivalent carbon dioxide emissions by 11 600 tons and the annual water consumption of the power plant by 251 027 tons.
PubDate: 2025-04-02
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- Numerical Study of the Stagnation-Flow Premixed Lean Hydrogen/Air Flame
Stabilized at the Wall with the Focus on NO Emission and Flame-Solid
Interaction-
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Abstract: In this study, we perform a numerical investigation of a steady laminar stagnation flow flame stabilized at a wall with the consideration of heat transport, focusing on a lean hydrogen/air mixture with a fuel/air equivalence ratio 0.6. We discuss the NO emissions and their formation rates under various conditions, such as flow velocity and combustion pressure. It is found that the predominant reaction pathway for NO formation involves NNH radicals, though this changes near the wall surface. Beyond examining the wall’s influence on flame structures, the present work focuses on the impact of combustion process on materials. Specifically, the accumulation of atomic hydrogen at the wall surface is explored, which is significant for the consequent modeling of potential hydrogen embrittlement. Additionally, the growth rate of oxide layers on the material surface increases significantly if the combustion pressure and consequently the combustion temperatures are enhanced. These investigations offer valuable insights into how combustion processes affect material, which is useful for designing engineering components under high-temperature environments.
PubDate: 2025-03-27
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- Influence of Internal Bypass Conditions on the Matching Characteristics of
Front and Rear Fans in the Three-Bypass Variable Cycle Engine-
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Abstract: In this study, a three-dimensional numerical investigation was conducted on the front and rear fans of a three-bypass variable cycle engine under various speeds and internal bypass conditions. The impact of internal bypass conditions and speeds on the matching characteristics of the front and rear fans, as well as the factors limiting the variation of bypass ratio, are summarized. The findings reveal that for near stall, design point, and near choke internal bypass conditions, the operating point of the front fan tends to move towards near-stall while that of the rear fan moves towards near-choke when increasing external bypass back pressure. At design speed, external bypass blockage is identified as a limiting factor for increasing the bypass ratio at the internal bypass design point. Additionally, blockage caused by a significant amount of low-energy fluid at the suction surface of the rear fan stator leads to rear fan stall which limits further increase in bypass ratio at external bypass near stall condition. Similarly, leakage flow overflow passage at the top section of first stage rotor blade in front fan results in front fan stall, which restricts decrease in bypass ratio at internal bypass near stall condition. As corrected speed decreases, there is an upper-left shift observed in the curve depicting variation in relative back pressure with respect to change in bypass ratio due to the phenomenon “pre-surge and post-choke”. This indicates increased air flow into external bypass resulting in higher values for lower speeds. Furthermore, limitation on further increase in bypass ratio at external bypass near stall condition with decreasing speed can be attributed to transition from rear fan stall to external bypass blockage.
PubDate: 2025-03-24
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- An Overview of the Heat Transfer Performance of Nanofluids in Spray
Cooling-
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Abstract: With the growing need for greater cooling capacity in electronic and heat exchange systems, significant attention has been directed toward improving the heat transfer by incorporating nanoparticles into the base fluid. While the use of nanoparticles in spray cooling shows promise for enhancing heat transfer, additional clarification is required. The paper compiles empirical data from existing literature focusing on spray cooling using nanofluids. Its objective is to clarify how nanoparticles impact the efficiency of spray heat transfer and investigate the effects of factors such as spray Weber number, nanoparticle concentration and droplet spread. Gathered data reveal that when compared to water droplets, nanofluid droplets exhibited more extensive surface spreading at low impinging droplet Weber numbers. Data also show that the heat transfer effectiveness of nanofluid sprays at the critical heat flux and film boiling temperature decreases with the increase in the spray Weber number. At the critical heat flux temperature and for intermediate spray Weber numbers, sprays utilizing nanofluids are more effective than sprays utilizing pure water; however, the situation reverses when dealing with exceedingly high Weber numbers. The data indicate that for surfaces heated within the film boiling range, it remains unclear whether sprays containing nanoparticles demonstrate higher heat transfer efficiency compared to sprays using pure water alone. For surfaces heated to the critical heat flux temperature, there is a critical nanoparticle concentration below which spraying with pure water is more effective than spraying with a nanofluid. However, for surfaces heated to temperatures near the Leidenfrost point, there is no clear indication that nanoparticle concentration plays a role. With the introduction of nanoparticles into sprays, there is a tendency for both the critical heat flux and the Leidenfrost temperatures to shift to a higher temperature range and to increase with the increase in nanoparticle concentration.
PubDate: 2025-03-21
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- Research and Development on Ramjet Combustion Instabilities
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Abstract: Recent research and development on ramjet and supersonic combustion ramjet (scramjet) engines is concerned with producing greater thrust, higher speed, or lower emission. This is most likely driven by the fact that supersonic/hypersonic propulsion systems have a broad range of applications in military sectors. The performances of such supersonic/hypersonic propulsion systems depend on a series of physical and thermodynamic parameters, such as the fuel types, flight conditions, geometries and sizes of the engines, engine inlet pressure/velocity. As a propulsion system, a stable and efficient combustion is desirable. However, self-excited large-amplitude combustion oscillations (also known as combustion instabilities) have been observed in liquid- and solid-propellant ramjet and scramjet engines, which may be due to acoustic resonance between inlet and nozzle, vortex kinematics (large coherent structures), and acoustic-convective wave coupling mechanisms due to combustion. Such intensified pressure oscillations are undesirable, since they can lead to violent structural vibration, and overheating. How to enhance and predict the engines’ stability behaviors is another challenge for engine manufacturers. The present work surveys the research and development in ramjet combustion and combustion instabilities in ramjet engines. Typical active and passive control of ramjet combustion instabilities are then reviewed. To support this review, a case study of combustion instability in solid-fueled ramjet is provided. The popular mode decomposition algorithms such as DMD (dynamic mode decomposition) and POD (proper orthogonal decomposition) are discussed and applied to shed lights on the ramjet combustion instability in the present case study.
PubDate: 2025-03-19
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- Progress in the Application of Absorption Cycles
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Abstract: The absorption cycle is a promising technology for harnessing low-temperature heat, playing a crucial role in achieving the objectives of carbon peaking and carbon neutrality. As a significant element in distributed energy systems, the absorption cycle can utilize various types of low-grade heat to fulfill cooling, heating, and electrical energy demands. Therefore, it can be employed in diverse settings to unleash its substantial energy-saving potential. However, the widespread adoption of the absorption cycle is limited to specific scenarios. Hence, further efforts are needed to enhance its technological maturity, gain societal acceptance, and expand its application scope. Focusing on the utilization of different low-grade heat, this paper provides an overview of significant advancements in the application research of various absorption cycles, such as the absorption refrigeration cycle, absorption heat pump, absorption heat transformer, and the absorption power cycle. According to current research, absorption cycles play a critical role in energy conservation and reducing carbon dioxide emissions. They can be applied to waste heat recovery, heating, drying, energy storage, seawater desalination, refrigeration, dehumidification, and power generation, leading to substantial economic benefits. The paper also outlines the primary challenges in the current application of the absorption cycle and discusses its future development direction. Ultimately, this paper serves as a reference for the application research of the absorption cycle and aims to maximize its potential in achieving global carbon neutrality.
PubDate: 2025-03-19
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- Performance Analysis of a Transcritical-Carbon-Dioxide Heat Pump-Driven
Deep-Dehumidification System Using Ionic Liquid Desiccant-
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Abstract: Traditional salt solutions, due to their susceptibility to crystallization and corrosion, can be replaced by ionic liquids (ILs) to enhance the effectiveness of liquid desiccant dehumidification systems. This study proposes integrating a transcritical-carbon-dioxide heat pump (TCHP) with an IL dehumidification cycle, thereby providing both cooling and heating for IL under large temperature differentials. Thermodynamic analysis is conducted to investigate the influence of key design parameters. The findings reveal that the TCHP is capable of handling the significant temperature rise during IL regeneration. The evaporation temperature is the key factor for matching the supply and demand of cooling and heating in the system. The self-circulation ratio of the solution is limited by the regeneration temperature. When the initial air humidity ratio is 8.0 g/kg and the supply air humidity ratio is 1.0 g/kg, the proposed system’s total heat COP is 31.9% higher than that of the reference systems.
PubDate: 2025-03-18
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- Heat Load Prediction of Building Rooms Using Only the Whole Building Data
via Heat Allocation Approach-
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Abstract: The next-generation heating systems, crucial for rational heat distribution and refined management, rely heavily on accurate zone-specific heat load predictions. This paper introduces a method for rapid zone-specific heat load prediction based on heat consumption allocation and data-driven techniques. The approach involves predicting the overall heat load of the building and then redistributing the total heat according to a heat consumption matrix. This eliminates the need for real-time data collection from each room, resulting in cost savings on hardware and improved computational efficiency. The overall building heat load data is obtained through a data-driven algorithm, while the heat consumption matrix is constructed through energy software simulation analysis. Using Building 2 in the Baotou Industrial Park, China, as a case study, the paper analyzes the differences between actual measurements and room estimates. Experimental results indicate an average error of 7.02% for the proposed estimation method. Although not achieving high precision (>95%) in heat load prediction, this level of accuracy is deemed sufficient to meet the requirements of feedforward control.
PubDate: 2025-03-15
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