Pressure Drop In Heat Exchanger Research Articles

Performance Analysis of Corrugated Twisted Tape Inserts for Heat Transfer Augmentation

This study explores the impact of wavy corrugated twisted tape inserts on enhancing heat transfer and reducing pressure drop in a double pipe heat exchanger. Cu inserts with twist ratios of 3.2, 4.2, and 5.2 were used to create turbulence in the inner tube. Varying water flow rates and measuring bulk mean temperatures at different points revealed significant improvements in heat transfer over smooth tubes. The insert with a 3.2 twist ratio achieved the highest Nusselt number increase (185%) and a 36.33% rise in the friction factor. These results highlight the effectiveness of wavy corrugated twisted tape inserts for optimizing heat transfer, with a 3.2 twist ratio identified as the most effective. Across Reynolds numbers from 4000 to 18000, Nusselt number increases were 77.75% for a 5.2 twist ratio, 167% for a 4.2 twist ratio, and 185% for a 3.2 twist ratio. Friction factors rose by approximately 10.42% for a 5.2 twist ratio, 32.54% for a 4.2 twist ratio, and 36.33% for a 3.2 twist ratio, demonstrating the relationship between twist ratio, heat transfer enhancement.

Numerical study on the influence of flow direction and fluid type on heat transfer and pressure drop in a two-tube spiral heat exchanger with innovative conical turbulators

In this research, numerical analysis will be conducted on the thermal and hydraulic performance of a spiral two-tube heat exchanger. The study employs an innovative turbulator design with curved outer blades and a semi-conical section with two openings. Numerical simulations were conducted using the commercialized Finite Volume Method (FVM) program, ANSYS FLUENT 18.2. The finite volume method was employed to analyze thermal and fluid equations and parameters. A comparison was made between two distinct flow directions, namely positive and negative currents, utilizing a comprehensive range of three working fluids. The numerical findings indicate that employing counter-current flow with a Water/MOS2−Fe3O4 fluid nanohybrid results in superior endothermic performance. These results indicate that a maximum thermal efficiency improvement of roughly 17.54 % and 8 % can be achieved by using the counterflow configuration with the nanohybrid fluid Water/MOS2−Fe3O4 at a mass flow rate of m˙ = 0.008 kg/s, in comparison to alternative models. Furthermore, the results showed that the Water/MOS2−Fe3O4 fluid nanohybrid performs better than the Ag-HEG/Water nanohybrid fluid when used in counterflow and parallel flow configurations, starting at a Reynolds number of 600. With a counterflow configuration in the two tubes, the Water/MOS2−Fe3O4fluid nanohybrid achieves the highest thermal performance coefficient in the two-tube heat exchanger.

Review on Nanofluids: Preparation, Properties, Stability, and Thermal Performance Augmentation in Heat Transfer Applications.

Nanoparticles play a crucial role in enhancing the thermal and rheological properties of nanofluids, making them a valuable option for increasing the efficiency of heat exchangers. This research explores how nanoparticle characteristics, such as concentration, size, and shape, impact the properties of nanofluids. Nanofluids' thermophysical properties and flow characteristics are essential in determining heat transfer efficiency and pressure loss. Nanoparticles with high thermal conductivity, such as metallic oxides like MgO, TiO2, and ZnO, can significantly improve the heat transfer efficiency by around 30% compared to the base fluid. The stability of nanofluids plays a crucial role in their usability. Various methods, such as adding surfactants, using ultrasonic mixing, and controlling pH, have been employed to enhance the stability of nanofluids. The desired thermophysical properties can be achieved by utilizing nanofluids to enhance the system's heat transfer efficiency. Modifying the size and shape of nanoparticles also considerably improves thermal conductivity, affecting nanofluid viscosity and density. Equations for determining heat transfer rate and pressure drop in a double-pipe heat exchanger are discussed in this review, emphasizing the significance of nanofluid thermal conductivity in influencing heat transfer efficiency and nanofluid viscosity in impacting pressure loss. This Review identifies a trend indicating that increasing nanoparticle volume concentration can enhance heat transfer efficiency to a certain extent. However, surpassing the optimal concentration can reduce Brownian motions due to higher viscosity and density. This Review offers a viable solution for enhancing the thermal performance of heat transfer equipment and serves as a fundamental resource for applying nanofluids in heat transfer applications.

A Microchannel Heat Exchanger Produced From a Metal Matrix Composite by Hybrid Laser Powder Bed Fusion and Inkjet Printing

Abstract This paper explores the production of an oxide dispersion strengthened (ODS) 304L stainless steel microchannel heat exchanger (HX) using a hybrid additive manufacturing process of laser powder bed fusion and inkjet printing. The study investigates the capabilities and economics of the hybrid inkjet-laser powder bed fusion (LPBF) process and evaluates the dimensional accuracy, functionality, and mechanical properties of the resulting ODS alloy. The effectiveness and pressure drop of the ODS heat exchangers produced by the hybrid LPBF tool are also determined. Results show that the inkjet-doped samples have a lower mean channel height with higher standard deviation than samples produced by LPBF alone. This is attributed to greater absorption of laser energy for the powder coated with the oxide precursor. The economic analysis shows that the hybrid process has a potential for reducing the unit cost of the heat exchanger based on cost modeling assumptions.

Booster heat pump with drop-in zeotropic mixtures applied in ultra-low temperature district heating system

The pursuit of sustainable district heating solutions has driven a growing interest in ultra-low temperature district heating (ULTDH) systems, where booster heat pumps (BHPs) play a pivotal role despite challenges posed by their efficiency limitations under large temperature glide conditions. This paper investigates the potential of drop-in R-1234yf/R-32 zeotropic mixtures in BHPs compared to a baseline R-134a system, within the context of a ULTDH framework. This study focused on the viability of the mixtures of R-1234yf/R-32 with the composition ratio of 80 %/20 % and 90 %/10 %. The investigation reveals disparities in compressor efficiency and heat exchanger pressure drop at the component level. Device-level analysis unveils increased COP for R-1234yf/R-32 mixtures, alongside with maximum second-law efficiencies reaching 0.32. A remarkable enhancement in heating capacity up to 58 % was found. System-level analysis demonstrated exergetic efficiencies and identified preferable district heating temperatures. Exergetic efficiencies of 0.47, 0.55, and 0.59 were achieved for domestic hot water preparation at district heating supply temperatures of 30 °C, 35 °C, and 40 °C, with a subsequent shift in optimal district heating temperatures as central heating station efficiency decreased. Temperature profile analysis underscored challenges stemming from excessive subcooling, highlighting the need for configuration refinements.

Prediction of heat exchanger efficiency using laminar heat transfer in swirling flow of radiated graphene oxide with nano fluid additives using machine learning technique

Nanotechnology has recently led to new possibilities for enhancing heat transfer in heat exchangers. The remarkable thermal characteristics of graphene oxide (GO)-based nanofluids with nanoscale additions have garnered significant attention in particular. When nanofluids and intricate flow patterns are involved, traditional analytical models frequently fail to appropriately forecast the efficiency of heat exchangers. Analyzed the phenomenon of laminar heat transfer in a heat exchanger that has a swirling flow of fluid dynamics, and pressure drop, and predicted the condensation heat transfer coefficient (HTC) of LHT. The functionalized radiated GO was chosen as nanomaterials in the present for the Pre-processing of Data Methods for managing outliers by machine learning (ML) models, like the CLAHE algorithm. The logarithmic mean temperature difference (LMTD) can be used to determine the temperature driving power for heat transfer within a heat exchanger. The Dynamic Smagorinsky Model (DSLM) and Wall-Adapting Local Eddy-viscosity (WALE) Model are turbulence models primarily designed for capturing turbulent behavior in fluid flows. The Kern technique and Hagen–Poiseuille equation are used for the pressure drop and pumping power needed in a shell and tube in laminar flow through a microtube based on Levenberg–Marquardt and Momentum Algorithm to predict Nusselt number and pressure drop in heat exchangers. The prediction sensitivity of the HTC by an LHT-trained ML model is used to evaluate the performance. The ML methods may be effectively used to forecast and maximize heat exchanger performance in the setting of laminar heat transfer in radiated GO nanofluid swirling flows. The accuracy score of 99%, demonstrating its exceptional predictive capabilities and results has great potential to improve energy efficiency, save operating costs, and advance sustainable practices in various industrial applications.

Numerical investigation of the effect of fluid nanohybrid type and volume concentration of fluid on heat transfer and pressure drop in spiral double tube heat exchanger equipped with innovative conical turbulator

Spiral heat exchangers in the heat transfer field have attracted researchers' attention due to their better heat transfer characteristics. This review discusses the increase in efficiency of this type of converter. to better understand the efficiency of the intended spiral exchanger, thermal efficiency (performance evaluation criteria) was chosen as the performance index in the present work, and the simulations were carried out in a calm regime (200<Re<800) and for two positive and negative flows and using three types of fluids. This study aims to conduct a numerical analysis of the impact of nanohybrid fluid type and fluid volume concentration on heat transfer and pressure drop in a spiral double-double-tube exchanger incorporating a conical turbulator. Computational fluid dynamics was employed in the study. The problem is tackled using ANSYS FLUENT 18 to conduct CFD simulations utilizing the finite volume method. The numerical findings indicate that employing countercurrent flow and a nanohybrid fluid of Water/MoS2–Fe3O4 significantly impacts overall performance, potentially boosting the spiral heat exchanger's efficiency by 8 %. The findings indicated that raising the volume concentration of the nanohybrid fluid Water/MoS2–Fe3O4 from 0.3 % to 0.5 % and 0.7 % leads to a notable enhancement in the thermal efficiency of this converter type. The converter achieves its peak efficiency at Reynolds number 200 when using the nanohybrid fluid Water/MoS2–Fe3O4, resulting in a 4 % and 17 % increase in thermal performance compared to the other two concentrations.

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.

Performance evaluation of novel plate-type condenser for an absorption/adsorption refrigeration system: Experimental and CFD study

Plate heat exchangers are widely used in many industries, such as refrigeration and air conditioning. Traditionally, the condenser in an absorption system comprises a shell and tube heat exchanger. However, we have innovatively replaced the conventional tubes with chevron plates in this system. The following variables were measured: condensation pressure (5.75–7.00 kPa), wall subcooling (0.2–1.8 °C), and channel Reynolds number (350–1400). In alignment with experimental results, the CFD simulation shows a higher condensation rate and large droplet size at the higher subcooling, and lower heat flux as the saturation pressure is decreased. Moreover, the overall heat transfer coefficient and the pressure drop of the chevron-type plate heat exchanger are increased by 1.60–5.00 times and 1.30–3.00 times, respectively, compared to the shell and tube condenser.

An Experimental Investigation of the Effects of Using Hexagonal BN–Water Nanofluids on the Thermal Performance and Pressure Drop of a Concentric Tube Heat Exchanger

The thermal conductivity of recently produced hexagonal boron nitride (hBN)-containing nanofluids is comparatively higher than their viscosity, indicating that these materials belong to a relatively novel class. In this study, hBN–water nanofluids in stable and dispersed concentrations were used in parallel and counterflow experiments at volumes of 0.01%, 0.1%, and 1%, as well as at various flow rates and Reynolds numbers. When employing hBN–water nanofluid in a counter-flow heat exchanger instead of distilled water, the results showed a 16.7% increase in the overall heat transfer coefficient. The findings also showed that, in comparison to a counter-flow heat exchanger, employing hBN nanofluid as the cold fluid in a parallel-flow heat exchanger produced superior results in terms of an increase in heat transfer. The effects of nanofluid concentration on pressure drops were investigated through experiments conducted in both parallel- and counter-flow conditions.

A novel TLFD-GA algorithm for multi-objectives optimization of ORC power plants with the effect of pressure drop considered

This research introduces a novel TLFD-GA algorithm for the three-level criteria optimization of organic Rankine cycle (ORC) power plants. It replaces the non-dominated sorting of NSGA-II with three-level fuzzy decision to simultaneously optimize environmental, thermodynamic, and techno-economic criteria. The algorithm provides direct optimization results without needing additional decision-making methods. Furthermore, the impact of pressure drop in plate heat exchangers is investigated, revealing a proportional relationship between pressure drop and the increment of evaporation pressure. A parametric study on 24 basic and recuperative trans-critical geothermal ORC systems indicates that compensating for pressure drop leads to a 5% decrease in thermodynamic performance, a 20% decrease in techno-economic performance, and a 20–60% increase in heat transfer area per net output power. After TLFD-GA optimization, the saving to investment ratio improves by an average of 4.5% across scenarios. R1270 stands out with a remarkable ratio of 3.13 and 4.32 in medium and high-temperature geothermal reservoirs. Moreover, the proposed TLFD-GA optimization algorithm has demonstrated its superiority in terms of superb convergence and stability when compared to NSGA-II, which suggests its prospective application in the low-carbon and green energy fields.

Heat Transfer and Pressure Drop in Plate Fin Heat Exchangers: A Numerical Approach

An apparatus for transferring thermal energy across an impermeable barrier between two or more fluids is a heat exchanger. The effective transmission of heat from a hot fluid to a cold fluid is its primary goal. The temperature differential between the two fluids directly affects this heat transfer. Using CFD study with FLUENT 2020 R1, the performance characteristics of the compact plate fin heat exchanger's improved surfaces are examined. The simulation of heat transfer and flow encompassed a variety of velocities including completely turbulent regions. The pressure, temperature, and velocity contours were taken from the Fluent simulations. To determine the heat exchanger's flow and heat transfer performance, numerical analysis has been done. Since boundary conditions are crucial to CFD, they have been carefully chosen. The flow field, heat transfer, thickness, and wavelength were all predicted using the software code for a range of air to water velocities. Three distinct wavelengths of numerical simulations for a plate-fin heat exchanger were used in the study (10, 20, and 30). There were changes to the fin thickness, entry locations, and air and water entry velocities. Solid Works and Ansys were used to create the geometry for the three-level fin models that were placed inside the heat exchanger, both with and without a cover. For determining the heat exchanger's geometry and fin isometry, three levels measuring 19.6 mm in height and 53.64 mm in width were constructed. The fins have a thickness of 0.2 to 0.4 mm. As the air and water velocities vary, so does the temperature inside the heat exchanger. Because the topmost layer is a warm stream's flow channel, the temperature rises there, whereas the opposite effect is seen close to the bottom layer. Convection heat transmission to the surroundings and conduction heat transfer through the heat exchanger's side plates are the causes of fluid temperature fluctuations in the depth direction.

Experimental investigation of pressure drop and heat transfer in minichannel with smooth and pin fin surfaces

This study investigates pressure drop and heat transfer characteristics in a minichannel heat exchanger experimentally. The experimental testing was carried out on a minichannel with a hydraulic diameter of about 2.5 mm, with smooth and embedded with circular pin-fins. The testing was conducted with different hot fluids, air and water, over different Reynolds numbers ranges, and over different heat capacity ratios (0.25, 0.5, 0.75, and 1). The experimental study of the pressure drop covers a Reynolds number range between 100-1900 for the hot water, and Reynolds number range between 500-10,000 for the hot air. The hot fluid flows through a channel with an inline arrangement with a 1750 pin fin, while the cold fluid flows through a smooth channel. Increasing flow rates resulted in an increase in pressure drop and heat transfer coefficients. When using pin-fins surface instead of smooth surface, the overall heat transfer coefficient (U) increased by 190% when water is used as the heat transfer fluid (HTF), and the same coefficient increased by 42% when air is used as the heat transfer fluid. Similarly, the difference in pressure drop is low in the case of water-water, while in the case of air-water, the difference in pressure drop is more substantial as Reynolds number increases.

Numerical and experimental investigations on the thermal-hydraulic performance of heat exchangers with Schwarz-P and gyroid structures

The fluid flow and heat transfer are investigated in high-performance heat exchangers with Schwarz-P and Gyroid structures using numerical and experimental approaches. This study was carried out first for laminar flow (Re = 10–100, Pr = 3–6) numerically and second for turbulent flow (Re = 1850–5500, Pr = 3.5) numerically and experimentally. All simulations were performed with COMSOL software to investigate the flow patterns, thermal performance, and pressure drop in heat exchangers based on the Schwarz-P and Gyroid with various unit cell numbers between 1 and 64. For low Re simulations, it is observed that the heat transfer coefficient and performance evaluation coefficient (PEC) increase with increasing the number of cells (or decreasing the cell size) in a constant volume. By redefining the Reynolds number based on the hydraulic inlet diameter and the velocity at the inlet of the structure, the Colburn and friction coefficients become independent of the structure's density. Correlations are provided to predict these coefficients. The results show that the Gyroid with 64-unit cells provides an average of 24 % (maximum 33 %) enhancement in the PEC and 40 % (maximum 46 %) Nusselt number improvement over the tube banks. On the contrary, the Schwarz-P does not have an improvement in PEC or Nusselt number compared to the tube bank. For the high Re study, several prototype heat exchanger samples based on the Schwarz-P and Gyroid structures were fabricated utilizing the FDM 3D-printing technique with no support structures to show that these heat exchangers could be manufactured. The SLM method was also used to fabricate a Gyroid heat exchanger for use in the experimental studies. The performance of a Gyroid heat exchanger made of AlSi10Mg has been tested for input flow rates ranging from 1 to 3 L per minute. For numerical simulation, the k-epsilon and K–W-SST turbulence models are employed and their results are compared with the present experimental data. It is found that the results of the K–W-SST model provide better agreement with experimental ones.

Heat Transfer Augmentation in Fin and Tube Heat Exchanger Embedded with Vortex Generators

The aim of this study is to investigate experimentally turbulent flow around tube by using multi–shapes of winglet vortex generators mounted behind the tube at different angles of attack, in order to investigate the effect of winglet on heat transfer and pressure drop of fin and tube heat exchanger placed inside a rectangular duct with Reynolds numbers (Re) ranging from (19000) to (49000). Fin-and-tube heat exchangers are frequently employed in a variety of industries, including power systems and air conditioning. The heating element inside the tube receives a power source ranging from (10W) to (40W). In these studies, vortex generators of the triangular and rectangular types are installed at various angles of attack (45° and 60°) on the fin surface behind the tube. The findings demonstrate that depending on the form and angle of attack of the winglets, utilizing winglet pairs has an impact on the heat transfer coefficient and friction factor relative to other designs. With increasing angle of attack, the friction factor and heat transfer coefficient rise. The optimal design for improving heat transfer is the rectangular type vortex generator, whereas the triangular type produces the least amount of heat transfer. The rectangular style of duct has the greatest pressure drop. For rectangular and triangular heat exchangers, respectively, the average Nusselt number is increased by 19% and 12%. The average Nusselt number of a fin and tube heat exchanger is increased by (16.7-17.8%) % for the rectangular type and by (9.3-10.6%) % for the triangular type at an angle of attack (β=60°) compared to (without winglet) case for Reynolds number ranging between (19000-49000), where the triangle type gives the least amount of heat transfer compared to other shapes.

An Analysis Of Flow Capacity Variation and Distance Between Louvered Strip Constant Angle 25o Of Heat Transfer and Pressure Decrease On The Heat Exchanger

This study aims to determine the effect of variations in flow rate and the louvered strip inclination angle on heat transfer in a double-pipe heat exchanger and the impact of variations in flow rate and inclination angle of the louvered strip on the inner tube pressure drop in a double-pipe heat exchanger. Three pieces of louvered strips at 50 mm, 70 mm, 90 mm are inserted into the inner tube of the heat exchanger with a constant tilt angle of 25°. Cold and hot water are used at a constant value where the cold-water flow rate is 600 liters/hour and V = 900 liters/hour, while the hot water flow rate is 1200 liters/hour. The inlet and outlet temperatures of both hot and cold water are measured, and the heat transfer characteristics of the heat exchanger are calculated as a result of the pressure drop that occurs in the inner tube due to the difference in height on the U-tube manometer used.

Experimental measurement of the pressure drop and heat transfer characteristics of a crossflow heat exchanger in low-density flows

NASA and other space agencies are currently planning the first human missions to Mars in the next 20 years. These missions will require much more power than current robotic missions, and so will require significant waste heat rejection capabilities to maintain steady state operations. Forced convection heat exchangers, particularly crossflow tube array compact heat exchangers, may offer significant volume- and mass-efficiency benefits over radiators for these applications. However, no experimentally validated correlations exist in the literature for the pressure drop and heat transfer characteristics of a forced-convection heat exchanger under the relevant dimensionless conditions which correspond to low (7-200) Reynolds number and moderate (0.0009-0.009) Knudsen number under axial and vortical flows. A staggered-tube crossflow heat exchanger has been constructed and its performance experimentally measured in a low-density wind tunnel. Data has been gathered in low-Reynolds, moderate-Knudsen conditions for both axial and vortical flows over a range of pressures and wall temperatures that is relevant to future Mars or high-altitude heat exchanger operation using both CO2 and air. The measured pressure drop exceeds what is predicted by correlations in the literature at very low (<75) Reynolds number while the Nusselt numbers were fairly well-predicted by existing correlations. A new correlation for pressure drop is presented for low-Reynolds, axial and vortical flow through a staggered circular tube array in crossflow.

Experimental and numerical analysis of heat transfer enhancement inside concentric counter flow tube heat exchanger using different nanofluids

The aim of this paper is to study experimentally and numerically heat transfer enhancement and friction factor inside a counter flow concentric tube heat exchanger using different volume fractions of CuO, Al2O3, and TiO2 nanofluids. Using nanofluids increases the thermal conductivity and conductive heat transfer coefficients compared to the base fluids. Increased heat transfer coefficients reduce the required tube length leading to reduced pressure drop in heat exchangers. Nanofluids have a high specific surface area, and therefore more heat transfer surface between particles and fluids is available. A standard k-ε turbulence model based on two equations was used in this investigation to solve the momentum and energy equations of nanofluids. The results were presented for Reynolds number range between 2000 and 12,000 and two different volume fractions of 0.05 and 0.2%, respectively. The numerical results illustrated that all the tested nanofluids exhibited better heat transfer coefficients compared with pure water. Particularly, CuO nanofluid illustrated the highest performance index for both concentrations. The performance index varied from 4.25, 3, and 2.5 to 1.5 for CuO, Al2O3, and TiO2 nanofluids, respectively, for the whole range of Reynold numbers. The results of this investigation may be used in designing heat exchangers-based nanofluids that can be used in many energy applications such as solar, energy production systems, and any industrial process.

Experimental Study on the Effect of TiO2–Water Nanofluid on Heat Transfer and Pressure Drop in Heat Exchanger with Varying Helical Coil Diameter

The growing demand for efficient heat exchangers has promoted extensive research in exploring advanced heat transfer fluids and novel geometries. This paper investigates the heat transfer and pressure drop characteristics in helical coil heat exchanger employing water-based TiO2 as nanofluid. The utilization of nanofluids offers promising enhancements in thermal conductivity and convective heat transfer in heat exchanger applications. The effect of nanofluid concentration and flow rate on heat transfer and pressure drop with varying helical coil diameter performance is investigated. Experimental tests were conducted using a heat exchanger with different helical coil pipe diameters of 9.53mm, 12.7mm and 15.88mm with constant pitch of 30mm and varying concentrations of TiO2 nanoparticles in water (ranging from 0.1% to 0.5% by volume). The heat transfer coefficient and pressure drop were measured at different operating conditions. The results shows that the addition of TiO2 nanoparticles to water significantly enhanced the heat transfer performance in the helical coil heat exchanger. There is an enhancement in heat transfer coefficient with increasing nanofluid concentration and with increase in pipe diameter. The maximum enhancement in heat transfer coefficient is observed at nanofluid concentration of 0.5% and for pipe diameter of 15.88 mm. However, there is increase in pressure drop with increase in nanofluid concentration and with decreasing pipe diameter. The pressure drop found to be higher for nanofluids compared to pure water. The maximum pressure drop is observed at a concentration of 0.5% and for pipe diameter 9.53mm. In conclusion, the use of a water-based TiO2 nanofluid in a helical coil heat exchanger offers improved heat transfer performance compared to pure water. However, the pressure drop also increases with nanofluid concentration and decreasing pipe diameter. Therefore, a trade-off between heat transfer enhancement and pressure drop should be considered in the design and operation of such heat exchangers.

Design and optimization of intermediate heat exchanger for lead-bismuth cooled fast reactor coupled with supercritical carbon dioxide Brayton cycle

Printed circuit heat exchanger has become a new choice for the intermediate heat exchanger of the lead/lead–bismuth cooled fast reactor coupled with supercritical carbon dioxide nuclear power system because of its large heat transfer area density, high power density and ability to work at high temperature and high pressure. In this study, the channel dimensions of the intermediate heat exchanger were optimized to improve its thermal–hydraulic performance. An in-house code for the thermal–hydraulic design of printed circuit heat exchanger with lead–bismuth and supercritical carbon dioxide as working fluid was built. The relationship between the cold side pressure drop of intermediate heat exchanger and cycle efficiency of the nuclear power system is revealed. The power density and pressure drop of the cold side are selected as two optimization objectives, and the multi-objective optimization process is conducted with the non-dominated sorting genetic algorithms II. The optimal design results of the intermediate heat exchanger are obtained with Pareto-front method. The Pareto-front shows that when the heat exchange density increases, the pressure loss of the cold side also increases, but more quickly than the former. Finally, considering the design limitations, the intermediate heat exchanger core design scheme is selected by the auxiliary function which considering both capital cost and operating cost.