Channel Printed Circuit Heat Exchanger Research Articles

Investigation of the thermal-hydraulic characteristics of SCO2 in a modified hybrid airfoil channel

The performance of printed circuit heat exchangers (PCHE) is critical to ensuring the efficiency and compactness of supercritical carbon dioxide (SCO2) Brayton cycle systems used in advanced nuclear energy. In order to improve the performance of the airfoil fin channel PCHE, the effect of the airfoil fin size on the channel performance is investigated and the effect of the airfoil fin arrangement parameters on the channel performance is analyzed by the Taguchi method. Particularly, a modified hybrid airfoil fin channel adapted to the changes in thermophysical properties of SCO2 is proposed. The results show that the heat transfer characteristics of the PCHE channel are enhanced and the flow characteristics are weakened with the reduction of the airfoil fin size, and the comprehensive performance firstly increases and then decreases. Taking the comprehensive performance of the channel as the optimization objective, the best combination of airfoil fin arrangement parameters is 2 mm for transverse spacing, 10 mm for longitudinal spacing, and 4 mm for staggered spacing. Compared with the traditional airfoil finned channel, the modified hybrid airfoil fin channel has significantly improved the comprehensive performance by 2.8%–13.2 %.

Heat transfer characteristics of printed circuit heat exchangers under mechanical vibrations

Purpose The purpose of this paper is to investigate the impact of mechanical vibration on the heat transfer and pressure drop characteristics of semicircular channel printed circuit heat exchangers (PCHEs), while also establishing correlations between vibration parameters and thermal performance. Design/methodology/approach By combining experimental and numerical simulation methods, the heat transfer coefficient and pressure drop characteristics of supercritical carbon dioxide (S-CO2) in a semicircular channel with a diameter of 2 mm under vibration conditions were studied. Reinforce the research by conducting computational fluid dynamics studies using ANSYS Fluent 22.0, the experimental results were compared with the numerical simulation results to verify the accuracy of the numerical method. Findings The use of vibration has the potential to attenuate the degradation of wall heat transfer caused by buoyancy-induced PCHEs on the upward-facing surface. The heat transfer enhancement (HTE) was maximized by an increase of 18.2%, while the pressure drop enhancement (PDE) was elevated by over 25-fold. The capacity to enhance the heat exchange between S-CO2 and channel walls through increasing vibration intensity is limited, indicating maximum effectiveness in improving thermal performance. Originality/value Conducting heat transfer experiments on PCHEs with mechanical vibration enhancement and verifying the accuracy of the vibration numerical model. The relation based on the dimensionless factor is derived. To provide theoretical support for using vibration to enhance the heat transfer capability of PCHEs.

Numerical investigation on flow and heat transfer characteristics of a PCHE with liquid lead–bismuth eutectic and sCO2 as working fluids

The Printed Circuit Heat Exchanger (PCHE) plays a critical role in the supercritical carbon dioxide (sCO2) power generation systems, directly impacting the efficiency of the Brayton cycle. In this study,A comparative analysis was conducted to assess the flow and heat transfer characteristics of liquid lead–bismuth eutectic and sCO2 in the combined channel PCHE, as well as in the straight channel and zigzag channel PCHEs. The results indicate that the combined channel configuration of the PCHE offers improvements in heat transfer performance without significantly increasing the resistance of liquid LBE. Additionally, this study analyzes the influence of fluid velocity, pressure, temperature, buoyancy forces and thermal acceleration on the heat transfer characteristics of the combined channel.Finally, the numerical calculation results are evaluated using typical heat transfer correlation equations from the literature to assess their applicability.

Comparing the partial cooling and recompression cycles for a 50 MWe sCO2 CSP plant using detailed recuperator models

Supercritical carbon dioxide (sCO2) power cycles are attractive for renewable energy technologies as they exhibit high thermal efficiencies, compact components, and reduced cycle complexity and levelized cost of energy (LCOE) relative to traditional steam power cycles. Consequently, numerous studies have investigated different layouts and operating parameters in search of an optimal cycle configuration. Two cycle layouts provide promising results, namely the partial cooling with reheating (PCRH) cycle, and the recompression with intercooling and reheating (RCICRH) cycle. Both cycles utilise recuperators with high heat transfer rates and literature suggests that the cost for the recuperators may account for a significant portion of the total plant capital expenditure. When modelling the recuperator, most cycle comparative studies employ simplified recuperator models where heat exchanger effectiveness or conductance is utilised to approximate heat transfer. These models do not consider the effect of recuperator size and geometry on heat transfer and pressure drop in detail. In this work, for a concentrated solar power (CSP) application, the performance and component size requirements of the cycles are evaluated parametrically for different cycle mass flow split ratios, pressure ratios, and ratio of pressure ratios across the compressors using detailed discretised one-dimensional (1D) recuperator models. Furthermore, the geometry of these models are optimised (by volume) for straight and zigzag channel printed circuit heat exchangers (PCHEs), widely accepted as the most suitable for this application. Finally, a high-level cost comparison is conducted. The results show that if appropriate pressure drop assumptions are made, a simplified model approach yields valid cycle level results when compared with the results obtained using detailed models which consider practical recuperator geometry. However, the pressures and temperatures within the recuperator may not be predicted to a sufficient level of accuracy. In addition to providing clarity regarding the interplay between key cycle process parameters and cycle performance, straight channel PCHEs provide better thermofluid performance than zigzag channel PCHEs. Furthermore, the RCICRH cycle requires larger turbomachinery and a marginally higher capital outlay for the power cycle, but offers superior thermal efficiencies and requires smaller heat exchangers. For sCO2-CSP applications employing dry cooling, this suggests that the RCICRH cycle requires a smaller solar field and cooling system, and may therefore offer increased revenue in adverse weather conditions where direct normal irradiance (DNI) is low and/or ambient temperatures are high. However, the PCRH cycle requires a smaller solar receiver system, a smaller thermal energy storage (TES) system, and smaller turbomachinery, the cost savings of which may outweigh the benefits of the RCICRH cycle.

Analysis of flow and heat transfer performance of different types of flow channels in printed circuit heat exchangers for pre-coolers

The shape of fins in flow channels of printed circuit heat exchangers (PCHE) significantly affects the heat exchanger performance. In the pre-cooler condition of the marine supercritical CO2 Brayton cycle power generation system, this study focuses on three typical discontinuous flow channel printed circuit heat exchangers. The investigation involves a numerical analysis of flow and heat transfer performance using CFD method. The comparative consequences illuminate that the rectangular fin channel exhibits the optimal heat transfer performance, and temperature drops are 1.18 times and 1.23 times, exceeding those of airfoil and rhombic fin channels, respectively. All three flow channels show different degrees of temperature drop reduction along the direction of fluid-flow. However, the rectangular fin channel demonstrates the worst flow performance, as pressure drops are 16.6 times and 17.8 times, higher than those of airfoil and rhombic fin channels, respectively. By calculating the values of Nu/f and Q/?p, the comprehensive performance of each flow channel is ranked from high to low airfoil fin channel, rhombic fin channel, and rectangular fin channel. This research provides guidance for optimizing the design and applying PCHE in engineering for marine supercritical CO2 Brayton cycle pre-coolers.

Investigation on thermo-hydraulic characteristic of lead–bismuth eutectic and supercritical carbon dioxide in a straight-channel printed circuit heat exchanger

The Printed Circuit Heat Exchanger (PCHE) is considered a promising heat exchanger for Lead-Bismuth Eutectic (LBE) cooled fast reactors due to its superior pressure-bearing capacity and heat transfer efficiency. This paper introduces a conjugate heat transfer solver to investigate the thermo-hydraulic performance of a straight channel PCHE incorporating LBE and Supercritical CO2 (S-CO2). A four-equation model is implemented in the solver to capture the low Prandtl number turbulent heat transfer characteristics of LBE. Comparisons with LBE circular tube experimental results demonstrate that the solver presented enhances the resolution of LBE heat transfer simulations. This improvement in numerical resolution is crucial for understanding and predicting the behaviors of LBE-S-CO2 conjugate heat transfer process. Building on this, the present work explores the impacts of inlet mass flow rate, inlet temperature, S-CO2 pressure, and geometric parameters on the thermo-hydraulic performance of the straight channel PCHE. In terms of inlet temperature, quantitative analyses emphasize the effectiveness of augmenting the mass flow rate on the S-CO2 side to enhance overall heat transfer performance of PCHE. Adjusting the inlet temperature of S-CO2 or LBE to increase the temperature difference between the two fluids improves the average heat transfer rate, but reducing the S-CO2 inlet temperature may decrease the overall heat transfer coefficient. Furthermore, increasing S-CO2 pressure positively affects the thermal conductivity and specific heat capacity of S-CO2, thereby improving the thermo-hydraulic performance of PCHE. Additionally, geometric parameter sensitivity analyses indicate that decreasing wall thickness or increasing ridge width improves heat transfer, but increasing ridge width may significantly increase PCHE’s volume. The increased channel length results in a higher pressure drop, simultaneously enhancing heat transfer. From the Performance Evaluation Criteria (PEC) perspective, lengthening the channel is advantageous for the S-CO2 side but unfavorable for the LBE side. Regarding channel width, reducing channel width yields a larger increase in PEC on the S-CO2 side compared to the LBE side. Therefore, narrower flow channels on the S-CO2 side seem more advantageous. The present work provides a numerical tool with higher numerical resolution for studying LBE-S-CO2 conjugate heat transfer process and offers valuable insights for straight channel PCHE design.

Numerical Analysis of the Thermal-hydraulic Performance of Supercritical LNG in Airfoil Fin PCHEs

Abstract As a novel, compact, and efficient plate-fin heat exchanger, the Printed Circuit Heat Exchanger (PCHE) is a prospective candidate for liquefied natural gas (LNG) vaporization at low-temperature and high pressure. Generally, the airfoil fin PCHE has better thermal-hydraulic performance than the zigzag channel PCHE. In this study, the thermal-hydraulic performance of supercritical LNG in PCHEs with different airfoil fin types and arrangements is investigated by numerical simulations. First, the effects of six different airfoil fin types, NACA0010, NACA0020, NACA0025, NACA0030, NACA 0040, and NACA 0050, on the thermal-hydraulic performances were studied. The results show that NACA0025 has the best comprehensive heat transfer performance. Then, the effects of staggered, vertical, and horizontal pitch of the airfoil fin arrangement on thermal-hydraulic performance were investigated. The results show that the optimal values of the dimensionless number for staggered and vertical arrangements are 1 and 4, respectively. The comprehensive performance does not change much when the dimensionless horizontal pitch number exceeds 3.0. Finally, the thermal-hydraulic performance of uniformly distributed, three front sparse and rear dense, and three front dense and rear sparse distributed airfoil fins was investigated. The results show that the front dense and rear sparse airfoil fins enhance and the front sparse and rear dense airfoil fins reduce the comprehensive performance compared to the uniform arrangement. The results show that a denser arrangement of airfoil fins near the quasi-critical point can improve the comprehensive performance while keeping the number of airfoil fins constant.

Theoretical analysis using thermal efficiency concept in straight micro channel printed circuit heat exchanger

The objective is to analyze the thermal and hydraulic performance in a Micro Channel Straight Printed Circuit Heat Exchanger. Counterflow and parallel flow configurations were analyzed for water cooling using ethylene glycol-based fluid and platelet-shaped non-spherical Boehmite alumina nanoparticles. The work presents results from applying a dimensionless theory that uses the concepts of thermal efficiency of heat exchangers and quantities associated with the second law of thermodynamics. Thermal efficiency, thermal effectiveness, thermal and viscous irreversibilities, thermodynamic Bejan number, and outlet water temperatures are presented in graph form. The data obtained allow us to conclude that the heat exchanger can work in a range of water and refrigerant flow rates below the design parameters. With the inclusion of nanoparticles with a volume fraction equal to 5.0%, the flow rates of the refrigerant fluid can be significantly reduced. The analysis performed shows that the use of nanoparticles improves the operational cost-benefit of the heat exchanger with a significant reduction in the hot water outlet temperature.

Design analysis of a printed circuit heat exchanger for HTGR using a 3D finite elements model

The intermediate heat exchanger (IHX) is a critical component in most of the High Temperature Gas-cooled Reactor plant layouts. The printed circuit heat exchanger (PCHE) has been studied as an advantageous candidate for this application last years. The extreme operating conditions of the IHX and the higher structural integrity of the PCHE over other heat exchanger technologies have motivated these studies. In this work, the structural assessment of a zigzag channel PCHE under IHX conditions was carried out by means of computational fluid dynamics (CFD) and Finite Element Analysis (FEA). The ASME Boiling and Pressure Vessel Code, Sections III and VIII, were applied to evaluate the safety operation of the PCHE. The temperature field in steady state was obtained using a 3D CFD model. Then it was used as thermal load to calculate thermal stress using a FEA model. The influence of the zigzag angle and the bend radius on the thermal and mechanical stresses was analyzed. Thus, the values studied for the zigzag angle were 0° (straight), 15°, 30 and 45°, while for the bend radius were 0.5 mm, 2 mm, 4 mm and 6 mm. The importance of the 3D temperature field to calculate thermal stress in a zigzag channel was evidenced due to the appearance of local temperature differences in the channel cross-sections. The change in flow direction created areas of higher local temperatures where the flow lines change their directions impacting the channel wall. A significant thermal stress concentration was found in these areas, and this effect intensified with increasing zigzag angle. The bend radius was decisive to reduce the thermal stress concentration when the zigzag angle was higher than 15°.

Heat transfer performance of liquid lead–bismuth eutectic and supercritical carbon dioxide in double D-type straight channel

• The thermal and hydraulic performance for LBE and SCO 2 in PCHE is simulated. • Effects of operational and structural parameters are analyzed in detail. • The heat transfer performance is evaluated based on PEC and GRA. The printed circuit heat exchanger is currently the most recommended heat exchanger type for the lead-bismuth eutectic fast reactor coupled Brayton cycle system. Here, the flow and conjugate heat transfer for lead-bismuth eutectic and supercritical carbon dioxide in a double D-type straight channel printed circuit heat exchanger was investigated using numerical simulations. The results indicated that the overall heat transfer coefficient was positively correlated with the mass flux of both lead-bismuth eutectic and supercritical carbon dioxide, with the latter having a greater effect. Moreover, increasing the temperature difference between the two fluids inhibited the heat transfer effect on the supercritical carbon dioxide side, while increasing the pressure reduced the overall heat transfer coefficient. Further, a reduction in the tube diameter and wall thickness strengthens the overall heat transfer efficiency through enhancing the turbulent kinetic energy of the fluid and reducing the heat transfer thermal resistance, respectively. A performance evaluation criterion and Grey relational analysis were combined to evaluate the heat transfer performance of the printed circuit heat exchanger, and the results showed that a smaller diameter and wall thickness, an increased inlet mass flow rate of supercritical carbon dioxide, and an appropriate reduction in the temperature difference would improve the heat transfer performance.

Numerical investigation on the Thermal-hydraulic performance of the modified channel supercritical CO2 printed circuit heat exchanger

Printed circuit heat exchangers (PCHE) are designed to improve heat recovery and energy saving in supercritical CO2 (S-CO2) power cycles. In the current study, a modified channel PCHE is proposed based on the regular straight channel and a zigzag channel. The thermal–hydraulic performance of four different types of PCHE is numerically investigated and the methods are verified by both experimental and numerical results. The numerical results are presented for a Reynolds number based on the inlet conditions between 5 000 and 25 000. From the numerical results, the local pressure loss and local heat transfer coefficients are analyzed and discussed. Subsequently, the global Nusselt number and Fanning friction coefficients are discussed. It is found that the inserted straight section contributes to uniform flow, resulted in significant pressure loss reduction with a slight decrease in heat transfer. The modified channel can reduce the Fanning friction coefficient by 33.1%-84.7% while the global Nusselt number reduction is about 3.6%-30.3%. This leads to a maximum performance evaluation criterion (PEC) enhancement of 45.9%.

The Effect of Flow Channel Geometry on Thermomechanical Performance of Printed Circuit Heat Exchanger (PCHE)

Abstract The carbon-free energy systems such as nuclear can benefit from compact and highly efficient heat exchanger technologies. The plate-type compact heat exchangers such as the printed circuit heat exchanger (PCHE) holds promise to fulfill these requirements. This work presents the thermal-hydraulic and structural analysis of PCHE for molten salt applications with thermal energy storage. In this study, three distinct types of geometry are chosen for the analysis, i.e., the zigzag channel type, the airfoil fin type, and the slotted fin type. For the working fluid, FLiBe (Li2BeF4) and solar salt (60% NaNO3 and 40% KNO3) are chosen for hot side and cold side, respectively. Titanium grade 5 is chosen as the structural material. The study is conducted by computational fluid dynamics (CFD) and finite element method (FEM) analysis. The thermomechanical behavior including pressure drop, fluid temperature, velocity profile, stress, and deformation of the flow channel were considered in this work. From the results, the zigzag channel geometry gives the best thermal hydraulic performance in terms of heat transfer and pressure drop. The structural analysis shows that the stress intensity has an exponential growth with power generation level with zigzag channel geometry being the highest out of three geometries. Overall, the zigzag channel PCHE is still the most suitable geometry for this application. Zigzag channel geometry should be substituted with an alternative geometry at a high-power application having both airfoil-fin and slotted-fin geometry at relatively identical stress intensity.

Thermo-Hydraulic performance of printed circuit heat exchanger as precooler in supercritical CO2 Brayton cycle

The Printed Circuit Heat Exchanger (PCHE) is one of the potential precooler candidates to be employed in the supercritical carbon dioxide (S-CO2) Brayton cycle with its high compactness, high efficiency and high endurance to extreme condition. Since the S-CO2 precooler operates in the condition close to the pseudo-critical region, it is of importance understanding the performance differences among different types of PCHE with the dramatical change of thermal-physical properties. Thus, in this study the effect of three channel configurations with zigzag, wavy and airfoil fin channel on heat transfer and flow resistance under precooler condition are investigated with numerical method. Based on the local analysis, it is found that the zigzag channel PCHE presents the better heat transfer performance compared to wavy and airfoil fin channel, and differences are increased as the temperature approaches the pseudo-critical region. Meanwhile, the airfoil fin channel shows the lower friction factor with only 6.12% and 41.31% of the zigzag and wavy channel, respectively. Furthermore, comprehensive performances are compared through the methods of entropy number, JF factor (ratio of Colburn j to friction factor) and Q/(ṁ∙ΔP) (ratio of heat exchange to pressure drop and mass flow). Based on the results, it is recommended for the airfoil channel to be adopted near the pseudo-critical region due to its larger surface area and smoother structural design.

Experimental study of propane condensation heat transfer and pressure drop in semicircular channel printed circuit heat exchanger

In this study, the propane condensation heat transfer and pressure drop performance of a printed circuit heat exchanger was experimentally investigated. 30 experimental cases with different mass flux, saturation pressures and vapor quality were conducted. By analyzing these data, a heat transfer correlation similar to the Akers et al. correlation was presented [19]. The newly proposed correlation has a mean square percent error of 5.9% over the equivalent Reynolds number range from 690 to 5600. For the condensing pressure drop correlation, the Lockhart and Martinelli correlation showed the best performance [27].

Experimental and numerical investigations of thermal-hydraulic characteristics in a novel airfoil fin heat exchanger

A novel airfoil fin (AFF) Printed Circuit Heat Exchanger (PCHE) with a 100 kW class heat transfer capacity was experimentally tested as a cooler in a supercritical CO2 system. Numerical analysis was also conducted to have an insight into the flow and heat transfer mechanism in the AFF channels. The results showed that the novel AFF structure has superior hydraulic performance as the pressure drop in the AFF PCHE is only about 1/6 of that in the zigzag channel PCHE with a comparative heat transfer rate. In comparison with the mass flow rate and operating pressure, the inlet temperature has relatively insignificant effect on the heat transfer rate and pressure drop in the AFF heat exchanger. The broadening of the fin has no obvious improvement in heat transfer coefficient but increases the friction factor massively, and thereby resulting in worse comprehensive performance in the fin channel. At smaller temperature and mass flow rate, the periodic fluctuations of the heat transfer coefficient and comprehensive performance criterion could be weakened significantly. In addition, the determinant effect of the effective thermal conductivity in the viscous sublayer and buffer layer on local heat transfer coefficient is also validated in AFF channels.

Multi-objective optimization based on economic analysis for a printed circuit heat exchanger with application to Brayton cycle

ABSTRACT Performance improvement of the printed circuit heat exchanger (PCHE) plays a vital role in improving the comprehensive performance of the supercritical carbon dioxide (S-CO2) Brayton cycle. In this study, three design parameters are selected to improve the comprehensive performance of a PCHE, including channel type, channel number, and channel length. The thermal effectiveness and the total cost are selected as the optimization objectives. And the total cost is based on the capital cost and the operation cost. For the optimal design of a PCHE, a simplified model is applied to obtain the heat transfer coefficient and pressure drop. The Pareto-optimal solutions and the corresponding design variables have been obtained after the optimization procedure. Then, the optimal results on straight channel PCHE are compared with the zigzag channel PCHE. Finally, we discuss the results of PCHE with different types of channels, and the design point is reported. The results show that the straight channel PCHE performs a better comprehensive performance than zigzag channel PCHE when it works under a small heat transfer rate.

Thermal Performance Analysis in a Zigzag Channel Printed Circuit Heat Exchanger under Different Conditions

In this study, the effect of axial heat conduction on thermal performance in a zigzag channel printed circuit heat exchanger (PCHE) with supercritical liquefied natural gas as the working fluid is studied by a numerical method under different conditions. The influence factors include Reynolds number, operating pressure, inlet temperatures of the cold side, and wall thermal conductivity. The results indicate that the axial heat conduction can greatly affect the thermal performance of the PCHE at low Reynolds numbers but decrease it at high Reynolds numbers for different working conditions. At the same average Reynolds number, the thermal performance of the PCHE decreases as the pressure increases, and the inlet temperature of 195 K provides the best thermal performance while the inlet temperature of 220 K is the worst among the three different inlet temperatures of the cold side. Furthermore, the reduction of wall thermal conductivity can improve the thermal performance of the PCHE due to the influence of axial heat conduction in the separation wall.

Optimization and heat transfer correlations development of zigzag channel printed circuit heat exchangers with helium fluids at high temperature

The printed circuit heat exchanger (PCHE) is an important candidate to be used as intermediate heat exchanger (IHX) in a High Temperature Gas-cooled Reactor (HTGR) plant due to its advantages in terms of safety, heat transfer and compactness. In this work, an analysis of the thermal-hydraulic performance of the zigzag channel PCHE within wide parameter ranges was conducted using computational fluid dynamics (CFD) techniques. The Nusselt number and the Fanning friction factor obtained from simulation were validated using experimental data available. To consider the interaction among parameters with a reduced computing time, the Taguchi method was used, which reduces the quantity of analyzed geometric designs. Optimized designs were proposed to reach the highest Nusselt number and lowest friction losses using the signal to noise ratio as objective function. It was found that the zigzag angle has contribution ratios around 50% and 70% on the values of pressure drop and heat transfer, respectively. Although the zigzag phase-shift was the parameter of least influence, its contribution ratio was close to 10% in the turbulent regime, which is comparable to the zigzag pitch length and bend radius contributions. As the most important contribution, Nusselt number and Fanning friction factor correlations were proposed as functions of the Reynolds number and the geometrical parameters. The new correlations were found to be more accurate as compared to existing ones in the literature.

Numerical investigation of thermal and hydraulic characteristics of sCO2-water printed circuit heat exchangers with zigzag channels

Since the precooler and the recuperator are the largest components of a supercritical carbon dioxide Brayton cycle, their design can substantially affect the performance and size of the whole system. Although the design of a precooler with zigzag channel geometry as an alternative to straight channels can reduce its size significantly, the applicability of available correlations (e.g. 0.7 < Pr<2.2) for the zigzag channel geometries is limited to the operational range of recuperators only. The current study, therefore, aims to develop correlations and understating of the complex flow and heat transfer characteristics in the zigzag channel printed circuit heat exchangers (PCHEs) operating under precooler conditions (2.2<Pr<13) of supercritical carbon dioxide Brayton cycle(sCO2-BC). Thermal and hydraulic characteristics of the PCHEs are computed numerically for a wide range of Reynolds numbers (5000<Re<7000) and Prandtl number (2.2<Pr<13). Also, a new data reduction method based on segmental averaged values has been proposed to handle adverse variations in the thermophysical properties of CO2 under precooler conditions. To ensure accurate evaluations, steep variations in the thermophysical properties of CO2 are implemented by supplying high-resolution real gas (RGP) property tables. Results suggest that thermal and hydraulic characteristics associated with zigzag channel vary substantially along the length of heat exchanger thus the conventional data reduction methods based on the channel average values cannot be used for true evaluations. Instead, segmental average values are used to develop pressure drop and heat transfer correlations for a broader range of Reynolds number and Prandtl number. The proposed correlations should be useful in the design of compact heat exchanger systems using zigzag channels for a wider range of cooling loads.

Investigation on Thermal-Hydraulic Performance in a Printed Circuit Heat Exchanger with Airfoil and Vortex Generator Fins for Supercritical Liquefied Natural Gas

In this study, the thermal and hydraulic performances of six different printed circuit heat exchanger (PCHE) configurations with supercritical liquefied natural gas as the working fluid are studied by a numerical method. Firstly, the thermal and hydraulic performances of the PCHE with airfoil fins are investigated at different operating pressures, which indicate that the PCHE with airfoil fins has better thermal performance but worse hydraulic performance when it operates at higher pressure condition. Furthermore, the effects of different PCHE configurations on the thermal and hydraulic performances are analyzed in detail. The results show that delta vortex generators (VGs) arranged upstream the airfoils can provide better thermal performance than VGs arranged downstream the airfoils, and the thermal performance of the common-flow-up configuration is not always better than the common-flow-down configuration. Finally, the overall heat transfer performance of PCHEs is evaluated by the volume goodness criterion under the same mass flow rate. The results show that the straight channel PCHE with front common-flow-up delta VG and airfoil fins has the best volume goodness factor among the six PCHE configurations.