Intermediate Heat Research Articles

Experimental analysis of a hybrid thermochemical cycle driven by intermediate grade heat sources for energy storage and combined cold and work productions

This paper presents an experimental study of a hybrid thermochemical cycle for the simultaneous cogeneration of cold and mechanical power, and thermal storage based on medium temperature sources. This concept is based on the integration of an expander machine on the reactive gas flow between the evaporator and the reactor to allow mechanical work production. The paper shows the proof of concept of this hybridization by continuous mechanical production and cold during the whole production phase: 68.33 kJ mechanical energy and 15.18 MJ cold, stable pressure ratio at the expander (around 1.3) and stable rotational speed (around 400 rpm). The prototype conception and design are detailed. The integration of the expander creates a pressure difference between the evaporator and the reactor (contrary to a classical thermochemical cycle), and thus an experimental sensitivity study investigating the effect of the cold production temperature at the evaporator (which defines the inlet pressure of the expander) on the mechanical production of the prototype and its dynamics is done. This allowed to analyze the strong coupling between the reactor and the expander in different operating conditions, experimentally and from a theoretical point of view. Indeed, the identified limitations of these two main components, it is worth mentioning that this is the first hybrid thermochemical prototype with stable output productions. The prototype works properly by providing continuous mechanical production during the whole production phase under different cold temperatures and constant electrical load, in comparison with what was found in the literature.

Two Stage Pulse Tube Cryocooler with Intermediate Heat Exchanger for accessing Regenerator Cooling Capacity

Conventional operation of closed-cycle two-stage GM-type Pulse Tube Cryocoolers (PTCs) usually relies on utilizing the cooling power of both the 1st and the 2nd stage. While the 1st stage is required to precool the 2nd stage to reach the lowest accessible temperature below 4K, it usually also provides enough cooling power to cool additional cryostat elements such as radiation shieldings. However, current applications in quantum physics have highlighted the need to additionally access heat sinks with intermediate temperatures and cooling powers, e.g. for cooling of superconducting wires. Here we will demonstrate a cooler configuration, where a third cooling stage is incorporated into the 2nd stage regenerator. This third intermediate cooling stage allows to extract 4-5 W of cooling power at temperatures between 8 K and 9 K for a standard two-stage PTC with a cooling capacity of 1.6 W at 4.2 K. Most importantly, this approach does not reduce the performance of the main stage but the added intermediate regenerator stage instead allows to tap into hidden cooling power of the PTC.

Analysis of the application of natural circulation of cooling media in shipboard reactor installations

In projects of floating facilities with a nuclear power plant, great importance is attached to the formation of a set of properties of the internal self-protection of the reactor, i. e. the development of properties that ensure its safety based on natural feedbacks, processes and characteristics. To do this, the RU project is based on physical patterns and technical solutions that prevent or minimize possible consequences from emergency situations. In particular, the natural circulation of the coolant in case of loss of power supply by the circulation pumps of the first round allows cooling the core after its transfer to a subcritical state. However, in order for a natural circulation to occur sufficient to ensure nuclear and radiation safety, certain conditions must be met in a particular case. The paper notes that the most important property of reactor installations of nuclear vessels is their ability to ensure natural circulation of the coolant in emergency situations, as well as when operating at capacity. This makes it possible to reduce the dependence of reactor plant safety on the technical condition of power supplies. Currently, natural circulation of auxiliary cooling media in passive safety systems is also widely used in reactor installations. These include emergency reactor cooling systems using an emergency cooling system, including using intermediate heat exchangers; reducing emergency pressure in the protective shell in case of an accident with a large coolant leak; cooling the reactor vessel in an out-of-design accident with the formation of corium. The paper proposes a method for preliminary analysis of the reactor plant’s ability to ensure natural circulation of the coolant, which allows us to compare various design solutions that contribute to an increase in coolant consumption during natural circulation. It is shown that for the operation of the reactor plant in stand-down mode and at energy power levels with natural circulation of the coolant, it is advisable to switch to boiling reactors. Passive safety systems using natural circulation have received special development on new nuclear vessels of projects 20870, 22220, 10510. Further development of safety systems using natural circulation to move cooling media is predicted.

Selection for heat tolerance in Atlantic salmon (Salmo salar) using reaction norms

Selection for heat tolerance is a key strategy for aquaculture to cope with the effects of climate change. Different alternatives exist to select aquatic species for heat tolerance. Here, we investigated the feasibility of applying reaction norms in summer growth of Atlantic salmon (Salmo salar) naturally exposed to diverse heat loads as a strategy to genetically improve heat tolerance. For this, summer growth of 40,044 fish from 2685 families and 21 cohorts, distributed across 14 years and 2 sites in Tasmania, was analysed under different reaction norm models (RNM), using a function of the average daily seawater temperature during the summer period (ranging from 12.8 to 19.7 °C) as the environment descriptor (heat load). RNM results unravelled substantial genotype by environment interaction for summer growth, specially between intermediate and high heat loads. Quadratic and spline linear-linear RNM outperformed linear RNM, showing a non-linear behaviour of the additive genetic effect on summer growth across different heat load gradients. The predictive ability of breeding values from RNM revealed opportunities to select for heat tolerance either for the highest heat load or for sensitivity to thermal variation (slope of RNM). Genomic-based breeding values presented better statistical properties than pedigree-based breeding values, highlighting the importance of using genomic information for a better predictive ability of heat tolerance. Genome-wide association analysis reinforced the polygenic nature of heat tolerance, indicating genomic selection as a more effective strategy to improve heat tolerance in Atlantic salmon, compared to strategies targeting specific genomic regions/genes.

Effect of recrystallization annealing, solid solution and pre-aging intermediate treatment on microstructure and mechanical properties of Al-Mg-Si rolled sheet

The intermediate heat treatment plays an important role in the severe deformation processing of aluminum alloys. In this study, the effects of recrystallization annealing, solid solution and pre-aging intermediate treatments on the microstructure and mechanical properties of Al-Mg-Si sheet were analyzed, and the strengthening ability of grain boundary, residual dislocation and precipitation was explored. The tensile results show that the pre-aging treatment can significantly improve the mechanical properties, increasing the yield strength, ultimate tensile strength and elongation by 22.9 %, 19.9 % and 10.9 %, respectively, compared with the alloy without intermediate treatment. Further studies present that the recrystallization annealed alloys are mainly composed of elongated recrystallized tissue and isometric crystals, and the strength enhancement is mainly attributed to precipitation strengthening. Solid solution treated alloys are composed entirely of fine equiaxed crystals with a higher density of residual dislocations, showing significant grain boundary strengthening and improving the plasticity. Pre-aging treatment obtains the benefits of solid solution treatment, while also forming a large number of GP zones and quasi-β'' phases, which impede the dislocation movement during cold rolling and then increase the effective nucleation sites of precipitation during T6 treatment. This promotes the generation of the strengthening β'' phase, and enhances the precipitation strengthening effect of the alloy from 165.7 MPa in solid solution treatment to 195.6 MPa in pre-aging treatment.

Heat resistance differences are common between both vegetative cells and spores of Clostridium perfringens type F isolates carrying a chromosomal vs plasmid-borne enterotoxin gene.

Clostridium perfringens type F isolates utilize C. perfringens enterotoxin (CPE) to cause food poisoning (FP) and nonfoodborne gastrointestinal diseases. The enterotoxin gene (cpe) can be located on either the chromosome or plasmids, but most FP isolates carry a chromosomal cpe (c-cpe) gene. Our 2000 article in Applied and Environmental Microbiology (66:3234-3240, 2000, https://doi.org/10.1128/aem.66.8.3234-3240.2000https://doi.org/10.1128/AEM.66.8.3234-3240.2000) determined that vegetative cells and spores of c-cpe isolates are more heat resistant than those of plasmid cpe (p-cpe) isolates, which is favorable for their survival in improperly cooked or held food. However, that 2000 article was recently retracted (90:e00249-24, 2024, https://doi.org/10.1128/aem.00249-24). To our knowledge, the 2000 article remains the only study reporting that heat resistance differences are common between both vegetative cells and spores of type F c-cpe isolates vs type F p-cpe isolates. To confirm and preserve this information in the literature, the heat resistance portion of the 2000 study has been repeated. The 2024 results reproduced the 2000 results by indicating that, relative to the surveyed type F p-cpe isolates, the vegetative cells of surveyed type F c-cpe isolates are ~2-fold more heat resistant and the spores of most surveyed c-cpe isolates are ~30-fold more heat resistant. However, consistent with several reports since our 2000 paper, one surveyed type F c-cpe isolate (which did not appreciably sporulate in 2000 but sporulated in 2024) produced spores with intermediate heat sensitivity, confirming that spores of some type F c-cpe isolates lack exceptional heat resistance.IMPORTANCEClostridium perfringens type F food poisoning (FP), which is the second most common bacterial cause of FP, involves the production of C. perfringens enterotoxin. While the enterotoxin gene (cpe) can be located on either the chromosome or plasmids in type F isolates, most FP cases are caused by chromosomal cpe isolates. The current results support the conclusion that the vegetative cells and spores of type F chromosomal cpe isolates are often more heat resistant than vegetative cells and spores of type F plasmid cpe isolates. Greater heat resistance should favor the survival of the spores and vegetative cells of those chromosomal cpe isolates in temperature-abused food, which may help explain the strong association of type F chromosomal cpe strains with FP.

Symmetrical Martensite Distribution in Wire Using Cryogenic Cooling

This article presents the results of research on a new combined process involving multi-cycle wire-drawing and subsequent cryogenic cooling after each deformation stage. For theoretical research, modeling in the Deform software was performed. The analysis of temperature fields and the martensitic component in all models showed that for both considered thicknesses, the most effective option is a low deformation velocity and the conduct of a process without heating. The least effective option is to use an increased thickness of the workpiece at an increased deformation velocity and the conduct of a process without of heating to ambient temperature, which acts as a local cooling of the axial zone of the workpiece with an increase in the workpiece thickness. An analysis of laboratory studies on this combined process revealed that in the absence of intermediate heating of a wire between deformation cycles, 100% martensite is formed in the structure. However, if intermediate heating to 20 °C between deformation cycles is carried out, a gradient distribution of martensite can be obtained. And, since the wire has a circular cross-section, in all cases, martensite is distributed symmetrically about the center of the workpiece.

Effect of Manganese on Cryogenic Toughness of 7% Nickel-added Steels with Intermediate Heat Treatment

Effect of Manganese on Cryogenic Toughness of 7% Nickel-added Steels with Intermediate Heat Treatment

A novel mass integration cogeneration system: Working fluid selection model and multi-criteria decision analysis

As the globe faces major difficulties such as climate change, environmental pollution, and limited energy resources, improving energy efficiency and decreasing the environmental effects of energy systems have become research priorities. A novel mass integration cogeneration (MICHP) system is proposed in this paper. In addition, a mathematical model relating the basic physical properties of the working fluid to the system's performance has been developed. R1233zd(E), R1224yd(Z), R601a, R245fa, and acetone have been chosen to be applied to the MICHP to confirm the model's accuracy. By utilizing the technique for order preference by similarity to an ideal solution, the entropy weight method, and energy, exergy, economic, and environmental analyses of the MICHP, the general efficiency of the working fluid is further explored. The results show that the intermediate heat exchanger is the largest exergy destruction equipment in the system. R601a has the highest return on investment of 0.53, and the annual operating cost is found to be proportional to the latent heat of the working fluid. R1233zd(E) has the lowest environmental impact, with a total equivalent warming impact of −4.89 × 106 kgCO2eq. The multi-criteria decision analysis of the working fluid agrees with the order of the proposed mathematical model's results, proving the model's accuracy. Consequently, the mathematical model can provide a helpful technique guide for working fluid selection in cogeneration systems.

A High-Temperature, High-Speed, Oil-Free Syngas Compressor for Small-Scale Combined Heat and Power

Abstract For low-emission, small-scale combined heat and power generation, integrating a biomass gasifier with a downstream solid oxide fuel cell system is very promising due to their similar operating conditions in terms of temperatures and pressures. This match avoids intermediate high-temperature heat exchangers and improves system efficiency. However, to couple both systems, a high-temperature and oil-free compressor is required to compress and push the low-density, high-temperature bio-syngas from the gasifier to the solid oxide fuel cell stack. The design and development of this high-temperature, high-speed, and gas-bearing supported compressor is presented in this work. An iterative process involving preliminary design, meanline analysis using commercial tools and in-house models is used for the design, which is then numerically analyzed using computational fluid dynamics. The goal is to achieve a design with a wide operating range and high robustness that withstands extreme working conditions. The 727 W machine is designed to run up to 210 krpm to compress 18.23kg/h of syngas at 350°C and 0.81bar. The centrifugal compressor has a tip diameter of 38 mm and consists of 9 backswept main and splitter blades. The impeller is made of Ti6Al4V and coated to prevent hydrogen embrittlement from the hot and highly reactive bio-syngas. The results obtained from the established models suggest a good concordance with the results from numerical analyses, despite the high temperatures and small scale of this design.

Multi-objective optimization and life cycle assessment of mass-integrated combined heat and power system

As the effects of climate change become more widely recognized, technical innovation and green energy will promote the growth of combined heat and power systems. This study proposes a novel mass-integrated combined heat and power system and conducts energy analysis, exergy analysis, and techno-economic analysis for the system. The optimization strategy integrated polynomial regression and non-dominated sorting genetic algorithm III is established, with system thermal efficiency, exergy efficiency, and return on investment (ROI) as objective functions. The system's environmental consequences are then assessed throughout its life cycle using life cycle assessment (LCA) under ideal operating circumstances. The findings reveal that the waste heat recovery heat exchanger has the highest exergy destruction in the system, with a value of 674.61 kW. Furthermore, the intermediate heat exchanger 1 and intermediate heat exchanger 2 (IHX2) with lesser exergy efficiency have an exergy destruction of less than 32.00 kW. The IHX2 is the most expensive equipment in the system, costing $90,931.19, but it also provides the most potential for system improvement. The multi-objective optimization findings suggest that the thermal efficiency, exergy efficiency, and ROI for the system are 0.17, 0.97, and 0.30, respectively. The LCA demonstrates that the system has a negligible influence on global warming and ozone generation with corresponding LCA findings of less than 4.20. The construction and operation phases of the investigation system have the most significant environmental consequences. The correlation between the raw materials necessary for the construction of the equipment in the system and the reaction temperatures, conditions, and waste composition during the preparation of the working fluids is large, so it is necessary to take corresponding environmental protection measures during production and processing to reduce the system's environmental emissions from the source and promote ecologically sustainable development.

A novel intermediate heat exchange intensified extractive pressure-swing distillation process for efficiently separating n-hexane-tetrahydrofuran-ethanol

The new intensified strategy can be used in special distillation processes to achieve energy savings. Through analyzing the influence of different extractants and pressure on the separation performance of n-hexane-tetrahydrofuran-ethanol. system, extractive pressure-swing distillation process (EPSD) using dimethyl sulfoxide as extractant was proposed. Multi-objective optimization was performed to definite the best operating parameters of EPSD. Based on the phenomenon that the temperature of high-temperature column top is lower than low-temperature column bottom, making it impossible to perform traditional thermal integration, an intermediate heat exchange intensified process (IHE-EPSD) was developed. The performance influencing factors and heat exchange network of IHE-EPSD were analyzed to obtained the optimal IHE-EPSD process. Three heat integration schemes of the IHE-EPSD were designed to further save energy consumption. Finally, the processes were assessed from economy, energy, environment and exergy. The results indicate that the IHE-EPSD process exhibits excellent separation performance, achieving the efficient separation of n-hexane-tetrahydrofuran-ethanol.

Effect of intermediate processing treatment on the structure and mechanical properties of Al–4 wt%Cu–3 wt%Mn alloy manufactured by electromagnetic casting followed by high-pressure torsion (HPT)

In this work, a thermally stable model Al–4Cu–3Mn (wt%) alloy has been manufactured by electromagnetic casting (EMC), followed by compression, intermediate heat treatment and high-pressure torsion (HPT). Structural changes of the alloy during subsequent processing stages have been analysed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and the X-ray diffraction (XRD). The results indicate that variations in the intermediate heat treatment temperature of the compressed samples lead to a significant difference in strain hardening and thermal stability after HPT. According to microstructure investigations the hardening of samples processed by HPT resulted from formation of mixture of grains and subgrains with high dislocation density as well as mechanical fragmentation of eutectic Al2Cu particles and precipitation of nanoscale Mn-rich dispersoids which are identified as Al6Mn. The intermediate heat treatment of the EMC rod at 350 ºC for 3 hours and heat treatment of HPT sample at 250 ºC for 5 hours exhibited the best mechanical properties in terms of ultimate tensile strength (UTS), yield strength (YS) and elongation (El), reaching 610 MPa, 560 MPa and 10 % respectively. At the same time intermediate annealing at 450 °C makes the HPT processing ineffective.

Design update of DEMO BOP for HCPB BB concept with an energy storage system

An option for the Intermediate Coupling Design (ICD) of the European Demonstration Fusion Reactor (DEMO) Balance of Plant (BOP) configuration for Helium-Cooled Pebble Bed (HCPB) Breeding Blanket (BB) concept consists of the Primary Heat Transport System (PHTS), the Intermediate Heat Transfer System (IHTS), using HITEC salt as coolant, equipped with a thermal Energy Storage System (ESS), and the Power Conversion System (PCS). The aforementioned BOP configuration is capable of producing electricity continuously during the pulse time (2 h) and dwell time (10 min) of DEMO plant operation.The present study reports on the current (2023) thermal system design of DEMO HCPB ICD BOP for 12 operational states defined by the DEMO Design Central Team (DCT) in 2021. It was shown that the PCS is able to accommodate all of the 12 operational points defined based on the uncertainties of the energy map, provided that an additional bypass line at the outlet of the Divertor Cassettes (DIV-CAS) Heat Exchanger (HX) towards the low-pressure part of the feedwater line (to the condenser in this investigation) is installed in the system. This line is activated only in the cases, where the feedwater flow to the low temperature DEMO heat sources HXs is needed to be higher than that necessary to remove BB power at the Steam Generators (SGs). In all the other cases, the bypass line remains unused. Additionally, perspective improvements of DEMO HCPB BOP regarding thermal ESS, as well as PCS are discussed.

Influence of silica fume addition and content on the early hydration of calcium aluminate cement – The role of soluble silicon

Hydration of a commercial white calcium aluminate cement (CAC) at 23 °C was modified by silica fume (SF) addition in varying amounts. The process was followed by heat flow calorimetry, quantitative in-situ XRD analysis and Gillmore needle experiments supplemented by pore solution analysis, thermodynamic modelling, and 1H-TD-NMR measurements. Lower SF/cement ratios accelerate the hydration of CAC. Higher ratios trigger an intermediate heat flow event, which is correlated to increased setting rates. This intermediate event (IE) initiates an induction period of constant duration, which appears later with increasing SF/cement ratios. Results show the IE is caused by an initially hindered CA dissolution, in which dissolved silicon provided by SF plays a crucial role. Increasing the [Si] concentration in the pore solution leads to a further retardation of the IE and eventually prevents the entire hydration reaction if a critical amount is reached. A detailed model explaining the observed behavior is proposed.

Development and Experimental Validation of a Two-stage Thermoelectric Heat Pump Computational Model for Heating Applications

The utilisation of thermoelectric technology as a heat pump in heating applications necessitates comprehensive investigation. The scalable nature of thermoelectric technology enables its operation at elevated temperatures without the requirement of refrigerants. In this work, an accurate computational model that can simulate one- and two-stage thermoelectric heat pumps is developed. This model uses the electric-thermal analogy and the finite difference method, including the thermoelectric effects, temperature dependent properties, thermal contact resistances and all heat exchangers, even the intermediate heat exchanger in the case of a two-stage configuration. Moreover, the model has been experimentally validated by built and tested prototypes, being the first time that a two-stage thermoelectric heat pump model is experimentally validated.The discrepancy between the simulated and experimental results is below the ± 10 % for COP, ± 8 % for generated heat and temperature lift in the airflow, and less than the ± 6 % for consumed power. Additonally, the model simulates real tendencies under different operating conditions, proving the reliability of the developed thermoelectric heat pump model.Finally, the model is used to optimise a thermoelectric system combining one- and two-stage thermoelectric heat pumps, and hybridising them with electric resistances. An airflow of 16.5 m3/h is heated from 25 °C to 160 °C, achieving a maximum COPtot of 1.21. Lastly, the importance of considering the thermal resistances of the heat exchangers is computationally modelled and demonstrated. Not taking them into account would overestimate the performance of the TEHP system by more than the 7 %.

Determination of the possibilities of using the universal low-temperature rotary apparatus for the production of meat and vegetable products under the conditions of providing uniform heat supply

The object of research is the process of frying a meat-vegetable product in the developed universal low-temperature rotary apparatus. The problem of ensuring the uniformity of the temperature field during low-temperature processing of meat and vegetable products is solved in the developed universal low-temperature rotary apparatus. The expected effect during the approbation of the apparatus is predicted under the condition of eliminating high-temperature intermediate coolants (hot air, etc.) due to the use of a film-like resistive electronic heater of the radiating type. The temperature field is established, which confirms the uniformity of the temperature effect on meat and vegetable products, and a slight deviation within the limits of autonomous exhaust fans is not critical and within the permissible error. Also, the introduction of Peltier elements into the design of the rotary apparatus will allow converting thermal energy into a low-voltage supply voltage (3–6 W) and, already at 20 °C, ensure autonomous operation of fans. The obtained results in the form of practical implementation of the developed apparatus will allow to implement low-temperature processing of meat and vegetable products. This allows to maximally preserve the functional properties of meat raw materials and the physiological properties of vegetable semi-finished products with a high degree of readiness. The practical implementation of the universal low-temperature rotary apparatus from the side of constructive implementation due to the use of functional containers makes it possible to obtain a wide range of assortment of meat products, both in the shell and without the shell. The elimination of high-temperature intermediate heat carriers (hot air, steam, etc.), their technical networks and generating apparatuss ensures energy and metal-intensive resource savings. In addition, the introduction of multicomponent vegetable semi-finished products of a high degree of readiness (powders, pastes, etc.) into the recipes of meat products will lead to a partial replacement of the main recipe components and an increase in the functional properties of the finished products.

Manipulation of strength and ductility of AA5182-O through cyclic bending under tension and annealing processing

Aluminum alloy (AA) 5182-O sheets are processed by continuous bending under tension (CBT) followed by heat treatment to investigate microstructural changes for optimizing strength and ductility of the alloy. Bending depth and pull speed parameters of the CBT process are optimized to enhance the achievable strain beyond a conventional uniaxial tension, by inducing significant microstructural changes in the sheets. CBT processed samples are subsequently heat treated at various time-temperature regimes to determine the best recovery condition. The combination of CBT and heat treatment effect on the mechanical properties is examined by the subsequent uniaxial tension experiment. Measured microstructural changes in terms of grain structure and texture by electron backscattered diffraction (EBSD) show that it is possible to change a 〈001〉 cube texture typically present in rolled and annealed AA sheets into a 〈111〉 fiber texture by combining CBT and annealing processing. Moreover, measured mechanical responses reveal that a particular combination of CBT and heat treatment at 270 °C for 2 h can increase strength by over 75 % at the expense of 37 % reduction of uniform ductility. Interestingly, only a complete recrystallization after CBT restores the r-value of as-received material, while the intermediate heat treatment conditions lower the r-value.

Optimization study of lead-based reactor heat exchangers based on Dakota coupling CFD

The lead-bismuth fast reactor is one of the fourth-generation reactor types.The microchannel heat exchangers are used as intermediate heat exchangers, which significantly influence the efficiency of supercritical carbon dioxide (S–CO2) Brayton cycle power generation. It is necessary to quantify the uncertainties and optimize the design of heat transfer and pressure drop of the microchannel heat exchangers. Due to the high cost and time-consuming problem of numerical simulation, this study employs the Arbitrary polynomial chaos expansion method to generate surrogate models for simulation calculations. Specifically, the microchannel parameters of the heat exchanger, namely flow direction spacing, transverse spacing, staggered spacing, and inlet velocity, are studied for the simulation. The pressure drop and convective heat transfer coefficient of the heat exchanger are considered as the objective functions for both simulation and optimization models. Uncertainty quantification analysis, sensitivity analysis, and optimization design of those parameters are conducted. By coupling DAKOTA with CFD, an optimization objective function is established to obtain optimal design data within specified ranges.

Study of fluid-elastic instability of the spatially bent tube structure in fast reactor intermediate heat exchanger

This study conducts a numerical simulation investigation on the flow field characteristics and fluid-elastic instability of the spatially bent tube structure in the intermediate heat exchanger (IHX) of a fast reactor. The inherent frequencies of the unique structure of the IHX spatially bent tube are calculated by using the wet modal method. They are employing Computational Fluid Dynamics (CFD) in conjunction with a fluid-structure coupling model, establishing an elastic tube model. Considering the bundle concentric circles arrangement, the “transition” arrangement is selected as the model to simulate the fluid-elastic instability. By the analysis of critical flow velocity, displacement, and the main vibration direction, the results indicate that the fluid-elastic instability of the tube bundle with a transition arrangement is mainly manifested by more severe vibrations in the bent tube segment. The instability flow velocity in the straight tube segment, ranging from 4.64 to 4.84 m/s, is greater than the instability flow velocity of 2.85 m/s in the bent tube segment. This study provides theoretical support for the design and operation of the intermediate heat exchanger in fast reactors, offering references for considering tube bundle arrangement and fluid-elastic instability in engineering practice.