Experimental Facility Research Articles

Near-limit detonation in long spiral tube: An improved experimental methodology and frequency analysis

In the present work, near-limit detonations in near stoichiometric propane-oxygen mixtures were investigated using a long spiral tube facility. Compared to previous studies, our improvements in the tube length, framing rate and resolution, image processing methods for distortion correction and detonation front detection, allow for a significant increase of the amount and quality of data obtained. As the initial pressure was decreased, stable, stuttering, and galloping regimes of detonation propagation were successively observed. The use of wavelet transform made it possible for the first time to visualize the change of the intrinsic frequency of the oscillation of the detonation front velocity during the highly unstable propagation in the stuttering and galloping regimes. The failure/re-initiation cycles produce the highest power density at frequencies in the range of 500–1000 Hz. In the stuttering regime, additional velocity fluctuations were observed in the range 2000–12000 Hz during the re-initiation events. In the galloping regime, velocity fluctuations took place during the low-velocity periods, with characteristic frequencies in the range of 2000–2500 Hz. The dynamics of the failure and re-initiation events were characterized in terms of induction length normalized wavelength. It was shown that in the stuttering regime, the detonation failure events occur after a quite random length, whereas the detonation re-initiation events appear to occur after a rather constant length. In the galloping regime, less variability was observed, and failure and re-initiation events occur at a rather well defined frequency.Novelty and Significance Statement1. Improved experimental facility and techniques to study near-limit detonations in long spiral tube2. First application of wavelet transform to study near-limit detonations3. Detailed study of the frequency of failure and re-initiation events in the stuttering and galloping regimes

The individual tubular low-toxic combustion chamber

BACKGROUND: intensive works in improvement and development of microturbine power plants for energy and transport continues worldwide. These works are still relevant due to near-to-zero emissions of microturbines, as well as due to the fact that microturbines efficiency can be increased up to 50% and above, which opens the potential to compete with well-known power plants in the foreseeable future, including in terms of efficiency. Therefore, the work on the study of a low-toxic combustion chamber for a microturbine seems relevant as well. AIM: Сomputational and experimental study of an individual tubular low-toxic combustion chamber of a 50 kW microturbine with an increase in pressure at the inlet to the chamber. METHODS: The description of the experimental facility for combustion chamber testing and the results of its experimental study are given. A sufficient convergence of the experimentally obtained parameters of the combustion chamber with the parameters obtained from the simulation modeling of flow and combustion in the combustion chamber was obtained. RESULTS: In the course of the calculated and full-scale studies, hydraulic losses, nitrogen oxide emissions, and temperature unevenness at the outlet of the combustion chamber with increasing air pressure at its inlet were determined. CONCLUSIONS: The calculated study showed a significant effect of an increase in air pressure from 3 to 3.5 bar at the entrance to the combustion chamber on its main parameters. Thus, hydraulic losses have more than doubled and nitrogen oxide emissions have increased almost 1.3 times. The conducted experimental study of the combustion chamber generally confirmed the results of mathematical modeling and thereby tested the computational model used. Thus, the discrepancy in the experimentally and computationally obtained values of relative pressure losses in the combustion chamber does not exceed 15%, and in emissions of nitrogen oxides 7%.

Development of the high temperature PbLi experimental facility for CFETR

Chinese Fusion Engineering and Test Reactor (CFETR) aims to demonstrate the fusion energy production up to 200MW, and finally reach commercial electricity power level 1GW. As one key component, the blanket is in charge of tritium breeding, neutron shielding and energy conversion. The liquid breeder blanket has many important advantages of simpler structure, tritium extraction and fuel replenishment online, as well as the high thermoelectric conversion efficiency. Moreover, the supercritical carbon dioxide (S-CO2) cOoled Lithium-Lead (COOL) blanket has been proposed for CFETR. However, the key issue of MagnetoHydroDynamics (MHD) needs further investigation, especially for the experiments. Therefore, the high temperature PbLi experimental loop is under development, which mainly includes three systems of PbLi, oil and water. The main components include the mechanical pump, main heater, cold trap as well as the superconducting magnet. At the test section, the mass flow rate, temperature and magnetic intensity will be up to 32 kg/s, 700 °C and 3T, respectively. In addition, the ultrasonic doppler velocimeter and potential probe instruments will be adopted to obtain the flow field. The main goal is to establish flow and heat transfer models, which are the critical input for the liquid breeder blanket design and optimization.

Efficient implementation of complex equations of state in a high-order framework

In the last decades, the interest in non-ideal compressible fluid dynamics (NICFD) flows and high-order accurate numerical methods, such as discontinuous Galerkin (dG), has quickly grown. In fact, advanced simulation capabilities are of paramount importance to develop new sustainable technologies with higher efficiency and low environmental impact, and to decrease the use of expensive experimental facilities. Nowadays however, the coupling of accurate Computational Fluid Dynamics (CFD) solvers with sophisticated thermodynamic models has been investigated mainly in the finite volume (FV) framework. Moreover, the solution of complex equations of state (EoS) has a too high computational cost for real-life use in industry, which is often overcome with the look-up table (LuT) interpolation approach. LuTs seem to be more suitable for FV solvers rather than high-order or finite element ones, since the interpolation error introduced may deteriorate the higher accuracy provided by these numerical methods. The novelty of this work lies in the assessment of an efficient implementation for real gas simulations in a high-order solver, by resorting to structured LuTs and automatic differentiation (AD). The proposed implementation is assessed with the computation of the inviscid and turbulent flow around a NACA0012. This approach guarantees an overhead of the computational cost around 17% with respect to an ideal gas solver with manually derived jacobian matrix.

The properties of sustainable aviation fuel II: Laminar flame speed

This work reports on the study of flame characteristics and laminar flame speeds (LFS) of sustainable aviation fuel (SAF) and conventional fuels (Jet-A1 and JP-5) premixed with air at elevated pressures. The experimental facilities included the constant volume combustion chamber (CVCC) and used a shadowgraph system to quantify the LFS. The effects of equivalence ratio and ambient pressure on the flame speeds were examined by varying the initial pressure 1, 2, and 3 bar (in addition to 0.1 and 0.5 bar for flame morphology) and the equivalence ratio from 0.8 to 1.8 at 423 K of temperature. The results indicated that JP-5 had the highest LFS value (90.1 cm/s) compared to the other two fuels. Jet-A1 and SAF have the same LFS result, which is less than a 15% difference, excluding the high equivalence ratio and initial pressure. The higher the initial pressure, the lower the LFS for all conditions. The equivalence ratio of 1.2 resulted in the highest LFSs. In addition, in order to understand the laminar flame speed of SAF and its combustion chemical kinetics. Therefore, the sensitivity analysis of SAF was performed. Results indicated that the chain branching reaction (O2 + HOH + O) positively enhanced flame speed as equivalence ratios (φ) increased, while chain propagation reactions, notably O2 + HHO2 (+M), had a negative effect on flame speed, particularly diminishing their influence at higher φ due to limited oxygen availability.

LITEC: An experimental facility for the validation of the IFMIF-DONES Impurity Control System

The Impurity Control System (ICS) of IFMIF-DONES is devoted to assuring lithium purity. After its circulation through the target, some undesired products will contaminate the lithium: deuterium, hydrogen, tritium, and beryllium. In addition, due to the high velocity of the flowing lithium, the target assembly, piping system, and other auxiliaries are subjected to a significant corrosion rate, thus leading also to the presence of metallic impurities in the liquid lithium (iron, nickel, molybdenum…). Finally, nitrogen, oxygen, and carbon will also be present.These impurities may compromise the operation of the facility: they may enhance the erosion/corrosion effect, shortening the operational life of equipment; they may be activated having an important impact on safety strategy, maintenance, and operational procedures; finally, the erosion caused to the target nozzle may produce fluid perturbations affecting to different aspects: fluid-dynamics, cavitation, and thermo-mechanics.The ICS extracts a fraction of the liquid from the DONES main lithium loop to be purified in dedicated traps, to maintain impurities below permissible levels to achieve the required safety and operational conditions.The validation of the ICS at a relevant circuit size will be performed in a new experimental facility called LITEC (The LIthium TEchnologies CIEMAT loop). It consists of a forced circulation lithium circuit. An electromagnetic pump provides a wide operational range for testing all the purification systems envisioned in the ICS. It has four test sections, where trap prototypes will be installed. An injection system also foresees the possibility of introducing impurities to simulate realistic IFMIF-DONES conditions. Finally, a specific branch will monitor online and offline the impurities.LITEC will contribute significantly to clarifying key aspects of the design and operation of IFMIF-DONES lithium systems and will be a reference facility for research activities in lithium technologies. In this work, its engineering design, operational parameters, and characteristics are presented.

Modeling of the influence of local heat sources on a light gas stratification formation and erosion in a large-scale experimental facility using eddy resolving numerical approach

The main objective of this work is to evaluate the results of application of Implicit Large Eddy Simulation (ILES) turbulence modeling approach to simulate the complex hydrogen safety problem. The paper presents the results of numerical simulation of the OECD/NEA HYMERES (HYdrogen Mitigation Experiments for Reactor Safety) HP2 series tests in the PANDA facility, aimed at studying the thermal effect of passive autocatalytic recombiner (PAR) operation on mixing the containment atmosphere, using CABARET-SC1 code. The code is based on the eddy resolving CABARET technique, which allows implicit modeling of the subgrid turbulence scales without using tuning parameters (ILES approximation). The natural convection flow inside the PAR model was calculated explicitly using a simplified model of the heating section and the housing. Good agreement of calculated transient with experimental data was obtained, which indicates the effectiveness of such approach.

148 Supplementing Bovacillus to newly weaned beef steers during a 90-d grazing period

Abstract This experiment compared performance, health, and physiological responses of high-risk stocker cattle receiving a Bacillus subtilis derivative during a 90-d grazing period. Crossbred steers (n = 120) were obtained from an auction yard and transported to the experimental facility. Steer shrunk body weight (BW) was recorded at arrival (d -1). This value was averaged with BW recorded on d 0 to represent initial BW (236 ± 2 kg). On d 0, steers were ranked by BW and allocated to 1 of 12 pastures (4-ha pastures; 10 steers/pasture). Pastures were randomly assigned to receive daily supplementation with dried distillers’ grains at 1% of BW containing either: 1) Bacillus licheniformis and B. subtilis ingredient (BOV; 2 g/steer daily of Bovacillus, Chr Hansen A/S, Horsholm, Denmark) or 2) no additive (CON). Cattle received treatments from d 0 to 90 while housed in pastures containing stockpiled grass forage, as well as free-choice access to water and a commercial mineral + vitamin mix without ionophores. Steers were assessed for bovine respiratory disease (BRD) signs daily, and shrunk BW recorded on d 91. Blood samples were collected, and BW recorded on d 0, 14, 28, 56, and 90. No treatment differences were detected (P ≥ 0.19) for glucose, non-esterified fatty acids, β-hydroxybutyrate, haptoglobin, or insulin-like growth factor 1, whereas a treatment × day interaction indicated increased cortisol in BOV cattle on d 56 (P < 0.01). A treatment × day interaction was detected for serum concentrations of parainfluenza type 3 antibodies, which was greater in BOV steers on d 90 (P < 0.01). No treatment differences were detected (P ≥ 0.23) for serum concentrations of antibodies against other BRD pathogen. Average daily gain (ADG) tended to be increased (P = 0.09) in BOV compared with CON steers from d 56 to d 90 (0.858 and 0.760 kg/d, respectively, although did not impact overall ADG (P = 0.48). No treatment differences were detected for steer final BW (P = 0.43). Total BW change per pasture was greater in BOV compared with CON (790 vs. 550 kg BW change; P = 0.02). No treatment differences were detected (P = 1.00) for BRD incidence, although steers removed from the experiment for health reasons tended to be increased in CON compared with BOV (P = 0.08). Despite lacking differences in health or physiological responses, B. licheniformis and B. subtilis supplementation increased overall production of BW in high-risk stocker steers during a 90-d grazing period.

88 Impacts of trace mineral source and ancillary drench on steer performance during a 60-day backgrounding phase

Abstract This experiment evaluated the impacts of supplementing organic complexed Cu, Co, Mn, and Zn on productive and health responses of high-risk beef cattle during a 60-d backgrounding phase. Crossbred steers (n = 120) were purchased at auction and transported to the experimental facility. Steer BW was recorded at arrival (d -1; initial shrunk BW = 227.7 ± 1.3 kg). On d 0, steers were ranked by BW and allocated to 1 of 8 groups (8 steers/group) and housed in drylot pens (6 m x 12 m) equipped with GrowSafe automated feeding systems (Model 8000; 2 bunks/pen; d 0 to 60). Groups were randomly assigned to receive a total mixed ration (TMR; 47% corn) containing: 1) sulfate sources of Cu, Co, Mn, and Zn (INR; n = 40); 2) organic complexed sources of Cu, Mn, Co, and Zn (AAC; Zinpro Availa 4; Zinpro Corp., Eden Prairie, MN; n = 40); or 3) AAC and an organic complexed trace mineral drench (APF; 30 mL/hd; Zinpro ProFusion, Zinpro Corp.) on d 0 and ancillary to morbidity treatment (n = 40). Diets provided the same daily amount of energy, protein, macro minerals and trace minerals based on 7 g/steer daily of Zinpro Availa 4. Steers were assessed for bovine respiratory disease (BRD) signs daily. Liver biopsies were performed on day 0, 28 and 60. Final BW was recorded on d 60 and 61. Blood samples were collected on d 0, 2, 6, 10, 13, 21, 28 and 45. No treatment differences were detected (P ≥ 0.23) for TMR intake, final BW, ADG, feed efficiency, or BRD incidence. Mean liver Co concentrations were greater (P = 0.02) in AAC and APF compared with INR steers. Mean liver Cu was greater (P = 0.02) in APF compared with AAC steers. Liver Zn tended to be greater (P = 0.10) on d 28 but less (P = 0.05) on d 60 for INR compared with AAC and APF steers. Plasma cortisol was least (P = 0.05) for steers supplemented with AAC on d 6, whereas AAC steers tended to have greater (P = 0.09) plasma cortisol on d 13 compared with APF. Plasma haptoglobin tended to be greater (P ≤ 0.10) for INR steers on d 28 and 45 compared with AAC and APF. While supplementing cattle with AAC or INR results in similar animal performance and clinical disease, AAC and APF reduces stress and acute phase protein responses.

EXPERIMENTAL STUDY OF FLOW PATTERNS AND PRESSURE LOSSES IN VERTICAL FLOWS OF OIL-WATER MIXTURES

In this work the experimental results of the dynamics of the two-phase oil-water flow patterns and the pressure gradients due to friction that they produce when conducting them in a vertical ascending pipe are shown. For the study, an experimental facility and two types of injection nozzles were built, constructed and characterized. The selected fluids were oil (viscosity 90 cP, density 885 kg/m3 with 28.3 API) and water. The measurements were made in a range of superficial speeds from 0 to 0.257 m/s for oil and from 0 to 0.684 for water. The experimentation was carried out using the two nozzles and in accordance with a test matrix that has as parameters the superficial speed of the oil (USO) and the superficial speed of the water (USW) for which a fixed value of the USW was taken and it varied the USO, although it was also worked in reverse. From the experimental results, the effect of the nozzles to induce the group of flow patterns and their respective pressure gradient is shown, which reaches its lowest value when conducting the oil in the annular flow scheme. The numerical results showed that there is a notable energy saving, since the pressure loss due to friction is up to 5 times lower when conducting the same amount of oil in the annular flow pattern. Key Words: Experimental installation, oil-water mixture, injection nozzle, flow patterns, annular flow, pressure gradient.

Ion-Exchanged Clinoptilolite as a Substrate for Space Farming

Clinoptilolite, with its structural peculiarities (ion-exchange and adsorbent properties), is an excellent candidate for direct use and various modifications. In this study, we explored the effect of ion exchange and the particle size of clinoptilolite on Raphanus sativus seed germination, plant growth, physiological and biochemical characteristics of plants. Plants were grown, for three consecutive runs, on non-modified clinoptilolite, 0.9–2.5 mm (C-2.5) and 2.5–5.0 mm (C-5.0); clinoptilolite fractions modified with ion exchange with ammonium (CNH4-2.5 and CNH4-5.0); and potassium (CK-2.5 and CK-5.0) ions. Our data revealed that ion exchange with ammonium increased water-holding capacity, while potassium exchange decreased the water-holding capacity of the substrates irrespective of their particle size. The positive effect of small fractions ion-exchanged clinoptilolite (CNH4-2.5 and CK-2.5) on seed germination, during the third run, was established. The small clinoptilolite fractions favored root crop production, particularly in CK-2.5 plants only during the first run. Substantial positive effect on the content of total carbohydrates and polyphenols especially during the third run was established in plants grown on potassium-exchanged clinoptilolite. Our findings support the future exploration of clinoptilolite as a suitable substrate for plant growth in space and ground-based facilities for space-oriented experiments.

Pre-test analysis of low power operations of STEAM, the EU-DEMO steam generator mock-up facility

While nuclear fusion reactors hold promise, their realization faces significant complexities, not only in the construction but also in managing the auxiliary systems required for safely operating plasmas. Pulsed plasma regime, integral to reactor normal operations, determines atypical operative conditions that can cause high thermal stresses on the components and generate instabilities. R&D activities are therefore required to characterize the components behavior in the extremely severe conditions of pressure and temperatures associated with fusion, especially during sudden power transitions. ENEA, as part of the EUROfusion consortium, is planning the construction of STEAM, an experimental facility aimed at qualifying the DEMO Steam Generator during pulse-dwell-pulse transitions within the W-HYDRA platform. Dedicated experimental campaigns will reproduce the low-power phase associated with the only material activation (dwell), the full-power phase (pulse) and the corresponding power transitions. This paper focuses on the low-power phase, presenting the performed RELAP5/Mod3.3 simulations, investigating the thermal-hydraulic performances of the system at 1 %, 5 % and 10 % of the nominal power, hence in conditions considerably different from fission standard practices. The simulation results are essential for defining regulation strategies for the SG test section and ensuring the correct operation of the entire system.

Reproductive qualities of sows of the large white breed of French breeding and their evaluation according to some breeding indices

The article presents the results of a study on the evaluation of sows by reproductive qualities using the selection index of reproductive qualities of the sow (SIRQS) and the index of Shatalina Yu. D. The experimental part of the work was carried out at Agroprime Holding LLC of the Odesa region and the laboratory of innovative technologies and experimental livestock facilities Institute of Pig Breeding and AIP of the National Academy of Sciences. Evaluation of sows for reproductive qualities was carried out considering the following signs: multifertility, head.; high fertility, kg.; nest weight at the time of weaning at 28 days, kg; preservation, %. A comprehensive assessment of sows for reproductive qualities was carried out using the selection index of reproductive qualities of the sow (SIRQS)and the Shatalina index. Biometric processing of research results was carried out according to generally accepted methods. The intrabreed differentiation of sows according to the selection index of the reproductive qualities of the sow (SIRQS) and the Shatalina index shows that a significant difference between the animals of the I and III experimental groups was found in terms of multifertility (4.3 and 4.4 head) and litter weight at the time of weaning at the age of 28 days (33.0 and 34.1 kg). There was no significant difference between the groups of experimental animals in terms of high fertility and survival of piglets until weaning at the age of 28 days. High coefficients of phenotypic consolidation in sows of the 1st and 2nd experimental groups were established by multifertility and litter weight at the time of weaning at 28 days. The number of reliable pairwise correlation coefficients between the absolute indicators of reproductive qualities of sows, the Shatalina index, and SIRQS is 75.0 %. The maximum increase in additional production was obtained from sows of the 1st experimental group of interbreed differentiation according to the index of Shatalina (+13.68 %) and SIRQS (+13.85 %), and its value is +697.34 and +706.01 UAH/head./farrowing, respectively.

Gravitational waves from composite dark sectors

We study under which conditions a first-order phase transition in a composite dark sector can yield an observable stochastic gravitational-wave signal. To this end, we employ the Linear-Sigma model featuring Nf = 3, 4, 5 flavours and perform a Cornwall-Jackiw-Tomboulis computation also accounting for the effects of the Polyakov loop. The model allows us to investigate the chiral phase transition in regimes that can mimic QCD-like theories incorporating in addition composite dynamics associated with the effects of confinement-deconfinement phase transition. A further benefit of this approach is that it allows to study the limit in which the effective interactions are weak. We show that strong first-order phase transitions occur for weak effective couplings of the composite sector leading to gravitational-wave signals potentially detectable at future experimental facilities.

The LiFIRE experimental facility: Final design, construction and experimental campaign

Recently, nuclear fusion-related experiments and dedicated facilities worldwide relying on the usage of liquid metals are experiencing a renewed interest.This is the case of the International Fusion Materials Irradiation Facility – DEMO-Oriented Neutron Source (IFMIF-DONES), a radioactive facility which will use several cubic meters of pure liquid lithium as a target for deuterons to produce high neutron fluxes having an energy spectrum as effective as the expected fusion reactors. The primary mission of IFMIF-DONES will be to irradiate selected candidate structural materials for building a comprehensive database on fusion material properties.Generally, alkali metals, such as lithium, exhibit safety issues related to their chemical reactive nature and material compatibility. Due to the wide uncertainty regarding the lithium behavior confirmed by an extensive literature review, a dedicated experimental facility has been conceived to primarily study lithium ignition conditions in support of the licensing process of IFMIF-DONES. The ultimate purpose of the LiFIRE facility will be to demonstrate by means of experimental evidences the set of requirements on lithium fire protection to be applied to the final engineering design of IFMIF-DONES.This work describes the final design, construction and experimental campaign of the LiFIRE facility currently under development at CIEMAT's premises.

Dancing ejecta

Splashing of impacting drops produces a myriad of secondary spray droplets, which generate aerosols during rain on the ocean and can cause health hazards during the spraying of pesticides or enhance the droplet transmission of disease. Determining the size and number of the finest splashed droplets is therefore of practical interest. Herein, we use a novel experimental facility with a 26 m tall vacuum tube, to study well-controlled drop impacts at velocities as high as 22 m s $^{-1}$ , where we reach parameter regimes not studied before using freely falling drops. Using extreme video frame rates, we pinpoint the primary source of the finest spray, coming from the catastrophic bending and rupture of the sub-micron-thick ejecta sheet, which emerges at a high speed from the neck connecting the drop and pool. The axisymmetric bending and convoluted ejecta shapes are driven primarily by resistance from the surrounding air, but also depend on the viscosity difference between drop and pool, which influences the initial ejection angle of the sheet. These extreme impact conditions provide new insights into general spray formation, through a sequence of bucklings of the rising ejecta, which dances next to the drop surface and can also form an enclosed air torus.

Materials adopted for particle beam windows in relevant experimental facilities

A beam vacuum window is a thin interface of separation between a volume under vacuum and a volume at a higher pressure traversed by particle beams. Their application is not only limited to particle accelerators, where they are typically installed inside the beamline to separate vacuum sectors, but also extends to other fields of nuclear research and to high-power hadron beam applications, such as spallation neutron sources and accelerator-driven systems. The main issue concerning the beam window technology resides intrinsically in the dual role of these components: the thickness of the window is supposed to be as thin as possible to allow the passage of the particles through matter with minimal interaction but, at the same time, enough resistant to maintain the required differential pressure between the two environments. Published by the American Physical Society 2024

Energy influence of the internal heat exchangers placement in a cascade refrigeration plant. A theoretical and experimental analysis

This paper deals with the analysis of the internal heat exchanger (IHX) impact on the energy performance of a cascade refrigeration plant (CRS) made up of two vapor compression cycles. Three IHX locations have been considered, the first one in the high temperature cycle (HTC), the second one in the low temperature cycle (LTC), and the third one thermally connecting the suction line of the LTC with the liquid line of the HTC. Additionally, five refrigerant pairs R134a/R744, R290/R744, R1270/R134a, R600a/R744, and R1234ze(E)/R744 and three different heatsink temperatures: 293 K, 303 K and 313 K have been considered. The experimental results, obtained in a CRS experimental facility, are contrasted with those obtained from a theoretical model. While theoretical results predict that the IHXs have mainly negative or neglecting effects on the energy performance of the CRS, the experimental ones results show that regardless of location and operating conditions, the activation of an IHX generally improves the COP, up to 5.6 % as a maximum improvement.

Model-Scale Reproduction of Fan Pressurization Measurements in a Wind Tunnel: Design and Characterization of a New Experimental Facility

In many countries, building airtightness is mandated by national regulations or energy efficiency programs, necessitating accurate measurements using the fan pressurization method. Given the significant influence of wind on measurement uncertainty and the need for reliable regulatory tests, experimental studies in a controlled environment are needed. This paper presents a novel experimental facility designed to replicate fan pressurization measurements on a model scale under controlled laboratory conditions. The key features of the facility include the ability to (1) conduct fan pressurization measurements, (2) generate steady wind conditions across varying wind speeds, and (3) accurately measure parameters like the pressure difference, wind speed, and airflow rate. The experimental facility includes a pressurization device, a wind tunnel, and a model representing a two-story house with nine distinct leakage distributions. A total of 96 fan pressurization measurements were executed using this setup, adhering to the similarity conditions specifically defined for assessing airflow errors due to wind. These tests followed the ISO 9972 standard, with the pressure differences ranging from 10 Pa to 100 Pa and steady wind speeds from 1 m·s−1 to 7.5 m·s−1. This experimental facility marks a significant advancement in understanding the effect of wind on building airtightness measurements.

Code development and preliminary validation for lead-cooled fast reactor thermal-hydraulic transient behavior

Lead-cooled fast reactors (LFRs) have a wide range of application scenarios, which require the thermal-hydraulic characteristics of LFRs to be reliable. In the present paper, the Lead-cooled fast reactor Thermal-Hydraulic Analysis Code LETHAC was developed, including the models of pipe, heat exchanger, and pool. To verify the correctness of LETHAC, two experimental facilities and three experimental cases were selected, including GFT and PLOFA tests for NACIE-UP and Test-1 for CIRCE. The calculated results show the same and consistent trend with the experimental data, but there are some discrepancies. It can be found that LETHAC is suitable and reliable in predicting the transient behavior of lead-cooled system.