High Heat Transfer Performance Research Articles

Review of enhancing boiling and condensation heat transfer: Surface modification

Data centers have tended to develop towards large scale and high density, with overall power consumption reaching up to 3 % of the total national electricity consumption. It is vital to establish energy-efficient electronic cooling devices for data center improvement. Phase-change heat transfer has emerged as a highly efficient method for addressing the heat dissipation problem. As the demand for micro-electronic cooling devices grows, enhancing the phase-change heat transfer has been a key focus of engineering research for several decades. Surface modification can effectively facilitate heat transfer favored by the surface area expansion and free energy transition. This review delved into the multiple processes involved in phase-change heat transfer, containing boiling and condensation. Considering the surface roughness and free energy, the wettability theories and manipulations of hydrophilic and hydrophobic surfaces were presented. The fabrication techniques available for modified surfaces mainly comprise coating, etching, template, sol-gen, and layer-by-layer assembly methods. The effects of patterned surface, wettability gradient surface, electrowetting surface, and wettability controllable surface on phase-change heat transfer enhancement were elaborated, particularly for the critical heat flux and heat transfer coefficients. This review of experimental and simulation results showed that surface wettability modification possesses a promising prospect in improving heat transfer performance. In this review, recommendations for the design of surface modification to promote the development of energy-efficient technologies in specific artificial environments were proposed. Further theoretical and experimental efforts need to create novel surfaces that can facilitate high-performance phase-change heat transfer across a range of applications.

Tube bundle evaporators with LGWP refrigerant R1234ze(E)

With new low-GWP HFO refrigerants, the heat transfer performances and methods for decreasing system refrigerant inventory are receiving increasing interest. In shell-and-tube heat exchangers, refrigerant distribution via pressurized liquid spray has the potential for high heat transfer performance while reducing refrigerant charge. However, no published studies have investigated LGWP refrigerants with spray evaporation on tube bundles. A test apparatus was constructed to measure the shell-side heat transfer coefficients of R1234ze(E) on bundles of tubes with two different enhanced-surface types and in two different bundle geometries at various refrigerant saturation temperatures. The results showed strong dependence on refrigerant properties, tube heat flux, enhanced-surface type, bundle geometry, and refrigerant inlet subcooling. The bundle heat transfer coefficients of R1234ze(E) were similar to that of R134a in the same test setup, usually within ±15% for similar conditions. In both cases, they first increased with the heat flux until a local maximum value was achieved. A localized dryout of the tubes at the bottom of the bundle penalized the overall bundle heat transfer coefficient at very high heat flux. For the condensing surface, bundle heat transfer coefficients rarely exceeded 10 kW/m2-K, whereas values in excess of 30 kW/m2-K were sometimes seen for the evaporating surface.

Numerical Investigation of the Heat Transfer Characteristics of Liquid Lithium Metal in Spiral Tubes

Abstract The application of liquid lithium as a coolant for the forthcoming era of space nuclear reactors exhibits significant potential, and spiral tube heat exchanger components are commonly used in steam generators for reactors. However, the heat transfer characteristics of liquid lithium in spiral tubes are not yet fully understood. This research establishes a non-isothermal heat transfer model incorporating a modified turbulent Prandtl number to analyze the flow of liquid lithium through spiral tubes with varying geometries. Numerical analysis is carried out focusing on the influence of inlet velocity, the distribution of related parameters, and the geometry of spiral tubes. The results demonstrate that in the range of the dimensionless Dean number 8165–13,063, the Nusselt number and the pressure drop present approximately linear relations with the Dean number. For the distribution law of relevant physical quantities, the inner side of the tube displays an eye-anatomy low-flowrate area and a high-temperature area, while a low-pressure area forms on the inner pipe wall. Finally, the pitch and spiral radius are found to be reduced as much as possible to ensure high liquid lithium-based heat transfer performance with a small pressure drop. The optimized design parameters reveal that within the actual design range of non-dimensional pitch of 0.667–10.667 and curvature of 0.0556–0.1667, the non-dimensional pitch and curvature are 0.667–2.667 and 0.1667, respectively. This study offers valuable insights into the heat transfer properties of liquid lithium within heat exchangers of the spiral tube design, promoting its application in space nuclear reactor power supply.

Numerical investigation on characteristics of the onset of nucleate boiling in petal-shape fuel rod bundle assembly

The helical structure of the petal-shape fuel element results in a high heat transfer performance. Therefore, it is crucial to analyze its thermal–hydraulic characteristics. However, research on subcooled boiling in the petal-shape fuel rod bundle assembly is few. The characteristic of subcooled flow boiling in rod bundle assembly with a 2 × 2 petal-shape fuel rod was investigated numerically by Computational Fluid Dynamics. The results show that the wall superheat at the onset of nucleate boiling (ONB) decreases with the increasing mass flux and inlet subcooling degree, but has the opposite effect with pressure. The prediction accuracy of existing ONB correlations was investigated. The majority of correlations, however, deviate from the simulated values. Because they were not intended for the ONB of the petal-shape fuel rod, they did not account for the effects of enhanced heat transfer

Rational design process for gas turbine exhaust to supercritical CO2 waste heat recovery heat exchanger using topology optimization

Advances in additive manufacturing (AM) technologies and topology optimization methodologies are enabling sophisticated novel designs for heat exchanger performance. These tools have been demonstrated for development of high-performance heat sinks considering local or component-level performance factors (e.g., heat transfer per volume). To leverage such capabilities in larger-scale energy systems, structured design methodologies are needed that consider system-level factors, such as production cost, cycle-level efficiency, and operational constraints. This study seeks to develop and assess a rational approach for designing thermo-economically optimal heat exchangers for such applications. The methodology is illustrated through development of the Primary Heat Exchanger (PHX) for a supercritical carbon dioxide (sCO2) power cycle recovering exhaust heat from a 6 MW-scale natural gas turbine. The proposed approach begins with a detailed thermodynamic cycle model, which is then extended to account for techno-economics. Next, an optimal PHX heat transfer capacity target is identified, and a high-level geometry is selected based on operating characteristics. This geometry is then divided into repeating 2D prismatic unit cells, for which topology optimization is applied to identify high-performance heat transfer geometries. A key aspect of this process is that the unit cell geometries are optimized using the total PHX mass as the objective function, which represents a surrogate for production cost. This leads to distinct designs compared with approaches that optimize local heat transfer and flow resistance factors. A second topology-optimized design is developed using a representative local thermal-fluid performance objective function and is found to require 1.6× the mass of the design generated with the system-level techno-economic objective for the same unit cell size. Conventional-type PHX designs with simple longitudinally finned tubes are developed for comparison, and are found to require total masses 1.5× or greater than the design obtained with the proposed process. Integrating this approach with detailed additive manufacturing costing models and experimentally validated fabrication constraints can yield a streamlined workflow for HX design for future energy systems.

The Effect of Angled Fins in Generating Swirling Flows with Vortices That Augment Heat Transfer Performance in an Annular Conduit

This paper examined the usage of thermally conductive angled fins within an annular conduit through numerical simulation. Despite the thermally conductive nature of the fins increasing heat transfer surface area, this investigation found that using an optimal fin angle can promote the generation of vortical structures which aid heat transfer. Using ANSYS-Fluent with the SIMPLEC algorithm and the SST κ − ω turbulence model, this research found that heat transfer performance improved considerably when the generated vortices were sufficiently large and robust. However, the type of generated vortex had a profound impact when optimising for higher performance evaluation criterion (PEC) values. Longitudinal vortices improved heat transfer performance with a low impact on pressure drop increase, unlike transverse vortices, which increased pressure drop significantly. The fin angles of 50° and 60° yielded high heat transfer performance without much increase in pressure drop, thus resulting in higher PEC values. Additionally, using fin heights that correlate to 20% to 60% of the gap between the concentric walls was ideal when designing heat exchangers to achieve higher PEC values. The results of this numerical investigation have been validated both theoretically and experimentally to ensure accurate reporting of the findings.

Heat transfer and pressure drop analysis of a microchannel heat sink using nanofluids for energy applications

Abstract The present research aims to enhance heat transfer in straight and wavy profile heat sinks using the same length and hydraulic diameter with different microchannel geometries (triangular, rectangular, trapezoidal, semi-circular, and circular) for uses in electronics, inkjet printing, high heat flux cooling of lasers, and other domains. The nanofluid employed is water/aluminum oxide (water/Al2O3), and the flow regime is laminar. The range of Reynolds number (Re) in this study was 220 ≤ Re ≤ 550, and the concentrations of nanoparticle Al2O3 with Heavy Water (2H2O) were 1.2 % volume. This investigation uses 3-dimensional Computational Fluid Dynamics (CFD) simulation software to investigate the heat transfer characteristics of several cross-sectioned microchannels. The numerical investigation utilizes the finite volume approach, and the CFD analysis is validated with accessible literature with different wavy profiles. According to the CFD simulation results, the microchannel with a circular cross-section has the highest heat transfer performance (up to 18 %) among the other cross-sections. The circular cross-section microchannel seemed to have the most significant increase in coolant temperature (by 9–22 %). The analysis outcomes prove that the microchannel with a circular cross-section has the highest performance for heat transfer; the triangular channel has the lowest performance under the same geometric parameters and boundary conditions. So, it is suggested that a circular microchannel can be used for a heat-carrying capacity of 150 W/cm2, a hydraulic diameter of 500 µm, and a Reynolds number equal to 500.

Experimental study on performance improvement of a household refrigerator with a flying-wing evaporator

In order to improve the performance of a household refrigerator, a flying-wing evaporator (FWE) is to replace the original finned tube evaporator (FTE). Different from the FTE, the fins of the FWE are formed directly on the tube by shoveling movement. Therefore, the FWE has high efficient heat transfer performance due to no thermal contact resistance between the tubes and the fins. According to different combinations of fin pitch and number of tube rows, three different structures of FWE are designed and tested in comparison with the original FTE on a double-door household refrigerator. The results show that the FWE shortens the cooling duration by 0.32 h (9.3%) and reduces the annual energy consumption by 4.28% with a 25% reduction in volume and a 13.5% reduction in refrigerant charge. This study proves that applying a FWE into a household refrigerator instead of the traditional FTE is one of the effective ways to decrease the volume of evaporator, reduce the energy consumption of refrigerator and enhance the effect of food preservation.

Experimental study on the parallel-flow heat pipe heat exchanger for energy saving in air conditioning

Energy saving significantly and positively affects energy conservation and releases less carbon dioxide. This study aims to investigate the energy-saving characteristics of a novel parallel-flow heat pipe heat exchanger (PFHP-HE) in air conditioning. It merged the characteristics of high axial heat transfer performance of heat pipe with high external heat transfer performance of parallel-flow heat exchanger (PF-HE). The test rig for the PFHP-HE was built on the basis of the heat transfer wind tunnel in this work. The heat transfer performance of parallel-flow heat pipe heat exchanger charged with R600A as the working fluid was experimentally studied. The filling rate of the heat pipe was 26%, and its thermal behavior was analyzed. The evaporation section of the PFHP-HE was heated by heating belt. The experiment was conducted with heating power of 500W. The experiments were performed with cooling air flow rates ranging from 63.36 m3/h to 118.08 m3/h. The results indicate that when the airflow rate was 118.08m3/h, the minimum thermal resistance of the PFHP-HE was 0.06 K/W, and the heat transfer efficiency was up to 98% in the experiments. As the pulsation phenomenon was caused by its small diameter, the temperature distribution in condenser had stratified phenomenon in PFHP-HE. The PFHP-HE has excellent heat transfer performance and working stability. The PFHP-HE is a promising heat exchanger for energy-saving in air conditioning. Its superior heat transfer performance and working stability make it an attractive alternative to conventional heat pipe heat exchangers.

Response surface methodology and desirability approach to investigate and optimize the performance of a CO2 geothermal thermosyphon

Geothermal thermosyphons (GTs) are increasingly used in many heating and cooling geothermal applications, owing to their high heat transfer performance. In this paper a combined response surface methodology and multi-objective desirability method is proposed for the investigation and optimization of the thermal performance of a geothermal thermosyphon. The filling ratio, temperature, and flow rate of the heat transfer fluid are selected as the designing parameters, and heat transfer rate and effectiveness are adopted as response parameters (objective functions). First, a dedicated experimental GT test bench filled with carbon dioxide (CO2) was built and subjected to different test conditions defined by RSM. A multi-level design of experiment-based response surface methodology (RSM) was used to establish corresponding models between the input parameters and responses. Various diagnostic tests were used to evaluate the quality and validity of the best-fit models, which explain respectively 98.9 and 99.2% of the output result's variability. Further, a surface response analysis of the effect of each input parameter on the responses was performed and a desirability function-based model was employed to determine the optimal combination of factors that would maximize the desired responses. The results revealed that the parameter-setting obtained using the proposed procedure satisfies the requirements of each response, with a desirability of 0.98.

S-CO2 flow in vertical tubes of large-diameter: Experimental evaluation and numerical exploration for heat transfer deterioration and prevention

Heat transfer deterioration (HTD) problems can undermine the thermal safety of heating tubes for supercritical carbon dioxide (S-CO2) flows. Relevant experimental evidence is highly desired, but most cases were investigated for small tube diameters (below 10 mm) and under limited operation parameters, far from the industry-scale applications. In the present work, large tubes (24 mm) are investigated experimentally with pressures of 7.5–15 MPa, mass flow rates of 100–1200 kg·m−2·s−1 and heat fluxes of 30–350 kW·m−2. The seriousness of HTD in large tubes was experimentally confirmed, and the mechanism is explored via a carefully-designed comprehensive comparison between present numerical simulations and experimental tests. Detailed analysis of vapor-like film development inspires us to mitigate the problem using structured-inner-surface, from the viewpoint of “supercritical pseudo-boiling”. This inspiration is further evaluated numerically: five types of enhancement structures are proposed to interfere with the development of vapor-like film. It was found that the proposed methods can fully prevent HTD problems, and especially the conical strips can achieve a high heat transfer performance (with performance evaluation criteria PEC of 1.21–1.35) and are thus recommended for HTD prevention in vertical large-diameter tubes under near-critical conditions. Overall, the experimental tests and numerical explorations can deliver more evidence on the theory and applications of supercritical fluid flow and heat transfer.

Evaluation of the integrated performance for floor heating using micro-encapsulated phase change material slurry

The micro-encapsulated phase change material (MPCM) slurry has the advantage of high heat transfer performance and heat capacity. Using MPCM slurry in the radiant floor heating (RFH) system could improve the indoor environment, but the overall performance was highly affected by heat transfer and pressure drop. In this paper, the flow and heat transfer model of MPCM slurry was developed and verified. The performance of serpentine and counterflow spiral structures was compared. Afterward, the optimized MPCM slurry material was selected as the heat transfer medium in RFH systems. Meanwhile, the flow and thermal performance of water and MCPM slurry were compared. Finally, the effects of different volume fractions and inlet velocities on integrated performance were investigated. The results indicated that the comprehensive performance of the serpentine system was better than the counterflow spiral. When the volume fraction was 15%, the comprehensive evaluation coefficients of three MPCM slurry heat systems are 17.9%, 22.9% and 13.8% higher than water respectively. MPCMS2 (n-dodecane) was suitable to use as the heat transferring medium in RFH system. Furthermore, as the volume fractions were 10%, 20% and 30%, the optimized velocities were 0.5 m s−1, 0.9 m s−1 and 1.1 m s−1, respectively.

Experimental study on the solidification and melting performances of magnetic NEPCMs composited with optimized filling metal foam in a uniform magnetic field

The present study experimentally investigates the magnetic nano-enhanced phase change material (NEPCM) filled with different strategies of metal foam in a uniform magnetic field for the solidification and melting processes. The thermochromic liquid crystals (TLC) technology is used to evaluate, compare and analyze the effects of magnetic field, partial filling (H = 0 h, 1/4h, 2/4h, 3/4h, 4/4h) and gradient porosity (positive and negative). The evolution of phase change interface, the temperature distributions and differences, solidification/melting rate, energy released/stored, and Nusselt number are comprehensively analyzed. The results show that the magnetic field inhibits convection but accelerates local heat transfer by the Kelvin force. As the porous filling height increases, the solidification rate and energy released increase firstly and then decrease. Comparing to pure PCM, the H = 3/4h case has the excellent solidification performance for 2.08 times increase and energy released for 40.22% improvement. The melting rate is advanced with the growth of filling height, but the energy storage capacity gradually decreases. In terms of heat transfer performance, the positive gradient porosity case owns best temperature uniformity and fastest phase change rate. Compared with pure PCM, its solidification rate and energy released are increased by 4.30 times and 36.7%, and melting time is reduced by 64.29%, but the energy stored is lost by 16.44%. As for the energy storage, the negative gradient porosity case can release and store more energy at the same time as maintaining high heat transfer performance.

Facile fabricant of slippery lubricant-infused porous foam-like surface for efficient fog harvesting

Inspired by pitcher plant, a variety of lubricant-infused surfaces have been created with unique properties. Owing to its high heat transfer performance and negligible contact angle hysteresis, the lubricant-infused surfaces are employed in fog harvesting. However, the loss of lubricant oil can result in performance degradation. Therefore, many surfaces with fine micro/nano structure have been created to increase the lubricant retention ability of lubricant-infused surface. Unfortunately, the procedures for preparing these surfaces are difficult or time-consuming. In this study, we synthesized a porous foam-like lubricant-infused surface (F-LIS). Porous copper foam was created on the surface of copper sheets through the dynamic bubble template method, and the pore walls were made of closely interlaced needle-like nano-dendrites. The fog harvesting efficiency of the surface can reach 2761.2 mgcm−2h−1. Additionally, F-LIS demonstrates excellent mechanical durability and chemical stability as a result of the micro/nano structure and the strong intermolecular force between PFPE as lubricant and the modifier layer, PFDT. After high-speed rotation, prolonged placement and UV irradiation etc., the surface still exhibits brilliant sliding ability and fog harvesting efficiency. This work offers a simple and effective approach for fabricating lubricant-infused surfaces with distinguished fog harvesting capability, providing a reference for relieving the crisis of freshwater resource scarcity.

Three-Dimensional Macroporous rGO-Aerogel-Based Composite Phase-Change Materials with High Thermal Storage Capacity and Enhanced Thermal Conductivity.

Three-dimensional porous network encapsulation strategy is an effective means to obtain composite phase-change materials (PCMs) with high heat storage capacity and enhanced thermal conductivity. Herein, macroporous reduced graphene oxide (rGO) aerogels with adjustable pore size are prepared by the emulsion template method and hydrothermal reduction process. Further, the shape-stabilized rGO-aerogel-based composite PCMs are constructed after the combination of 3D porous rGO supports and paraffin wax (PW) through vacuum melting infiltration. By regulating the pore structure of the rGO aerogel network, the rGO-based composite PCMs achieve excellent energy storage properties with a phase-change enthalpy of 179.94 J/g for the loading amount of 95.61 wt% and an obvious enhancement in thermal conductivity of 0.412 W/m-1·K-1, which is 54.89% higher than pristine PW and enduring thermal cycling stability. The obtained macroporous rGO-aerogel-based composite PCMs with high thermal storage and heat transfer performance effectively broaden the application of PCMs in the field of thermal energy storage.

Numerical thermal–hydraulic analysis and multiobjective design optimization of a printed circuit heat exchanger with airfoil overlap fin channels

AbstractIn this study, we numerically investigated the performance of a printed circuit heat exchanger (PCHE) featuring National Advisory Committee for Aeronautics (NACA) 0020 airfoil overlap fins integrated into its straight flow channels. Numerical simulations were performed by solving Navier–Stokes and energy equations to analyze liquid water at temperatures ranging from 30 to 90°C, which is possible for use with a geothermal heating system, for example. The optimization of the PCHE airfoil fin geometry is performed using nondominated sorting genetic algorithm II (NSGA‐II) with three design features: front, back, and overlap lengths. The effectiveness and pressure drop of the PCHE are evaluated as two objective functions. The present study shows that, when a Reynolds number falls between 1088 and 5000, the overlapping airfoils exhibit lower pressure drops and higher convective heat flux relative to the separate airfoils, and an increase in overlap length always decreases the pressure drop positively. It is also found that using overlapping airfoils of front length of 0.1 mm, back length of 0.119 mm, and overlap length of 0.203 mm leads to almost the same effectiveness and a 22% decrease in pressure drop (which is generally believed to preferably maintain the high heat transfer performance and minimize pressure drop, as a favorable design), compared to a base design of the airfoils with front and back lengths of 0.2 mm and an overlap length of 0.1 mm.

Temperature-dependent wicking dynamics and its effects on critical heat flux on micropillar structures in pool boiling heat transfer

Boiling heat transfer is a vital process that needs to be incorporated into next-generation cooling systems due to its high heat transfer performance. The critical heat flux (CHF), which defines boiling performance, needs to be enhanced to expand the operating limits of heat transfer applications. The crucial factor enhancing CHF is wicking performance, i.e., liquid-supply capacity during the boiling process. This study investigated the relationship between wicking performance and CHF enhancement using micropillar structures of various roughness (diameter: 4–20 um and gap: 10–40 um). To measure wicking performance near the boiling condition, we increased the surface temperature from 20 °C to 95 °C. At the highest temperature (95 °C), the D04 G10 sample (i.e., highly-roughness) showed an enhanced wicking coefficient (6.8 mm/s0.5), 48% higher than the value measured at room temperature. For the boiling tests, the D04 G10 sample (∼164 W/cm2) showed a notable CHF enhancement of 85%, compared to the plain surface (∼89 W/cm2), owing to the strong liquid flow induced by wicking, which delayed vapor film formation. Based on these results, we proposed a new CHF correlation that accounts for the wicking performance near the boiling condition, which is accurate within an error of 9% with experimental results.

Parametric study of DBD plasma actuator for heat transfer enhancement in flow over a flat plate at low Reynolds numbers

The present study intends to find the optimal configurations of Dielectric-Barrier-Discharge (DBD) plasma actuators to augment the thermo-hydraulic performance in air flow over a flat plate at low Reynolds numbers. A range of parametric studies are conducted to determine the impact of the major contributing variables; Reynolds number, voltage frequency, and the applied voltage of the DBD actuator, on the heat transfer. This study reports that in the presence of plasma actuation, the factor of enhancement (Num/Num0) achieves about 3.76. Results show that reducing the Reynolds number and raising the frequency and applied voltage of the DBD actuator improve the factor of enhancement. Furthermore, the plasma system thermal efficiency (PSTE) to achieve the optimized electric power consumption and heat transfer augmentation is introduced as the rate of increase of enhancement factor to the rate of increase of consumed electric power. The frequency and applied voltage for the DBD actuator are used as the design variables to find the optimum configurations. Optimum electric power consumption and configurations of DBD plasma actuator based on Reynolds number are determined. Results also show that Vapp = 10.5 kV and f = 5 kHz conditions for DBD plasma actuator is much beneficial than the other configurations in the presence of low Reynolds number external flow. This study's findings will benefit designers in developing high-performance heat transfer.

Comparative studies of fluid mixing and heat transfer behaviors in a millimeter scale T-type mixer with triangular baffles

In chemical processes, fluid mixing and heat transfer efficiency are very important. To guarantee high mixing efficiency and heat transfer performance during chemical processes, we designed and embedded triangular baffle structure in millimeter-sized T-type mixers. Through Computational Fluid Dynamics (CFD) simulation and visualization experiments, the influence of triangular baffle on the heat transfer performance of mixing was studied. The results show that visualization experiment verifies the reliability of the model. Compared with T-mixer, the mixing index (M) of the T-mixer with double triangular baffle (DTB) has increased by 88.2% and the Nusselt number (Nu) has increased by 32.9%–65.2%, which shows that DTB has a good effect of enhancing mass and heat transfer. The Performance Evaluation Criterion (PEC) of DTB is within 1.22–2.43, which is 3.1%–24.5% higher than single triangular baffle (STB), indicating that DTB has good hydrothermal performance. The PEC is larger at medium to low Reynolds number (Re < 200). In addition, compared with the mixers reported in the literature, the M and Nu of T-type mixer with DTB have increased by 4.5% and 14.2%, respectively. It indicates the superiority of the structure in enhancing mass and heat transfer. The present study can be used to enhance mass and heat transfer in laminar flow.

Simulation of steel corrosion and iron yield in LFR with lead coolant

Liquid lead is the main coolant of the fourth generation of advanced nuclear energy system — lead cooled fast reactor (LFR), due to its good neutron economy, high heat transfer performance, stable chemical properties, constant low melting point, high boiling point, etc. Although there are many advantages, the corrosion of metal materials in liquid lead is one of the decisive factors restricting the development of lead cooled fast reactor. In this study, an engineering model for simulating the oxide film growth in liquid lead coolant is established, and the time-dependence of steel flux is analyzed based on the experimental data in the literature. The effects of circuit temperature, hydraulic diameter of section simulated, coolant velocity and steel types on the steel corrosion were investigated. The results showed that the oxide film formed on the steels is of micron grade and the diffusion yield of iron produced in pure lead coolant is of kilogram grade after ten years’ corrosion. The temperature and the coolant velocity have significant effects on the steel corrosion while the effect of hydraulic diameter is mild. Also, the steel types affect the growth of oxide film. The findings provide basic data for the evaluation of radioactive corrosion products of LFR.