Large Heat Transfer Coefficient Research Articles

Thermodynamic performance and flow structures analysis of supercritical CO2 applied in a regenerative cooling channel mounted with mini-ribs

Supercritical CO2 (SCO2) is regarded as a promising supplementary coolant for traditional regenerative cooling at extremely high flight speed (Ma ≥8) due to its superior heat and mass transfer capability. Using sCO2 as the coolant, mini-ribs is introduced to the rectangular regenerative cooling channel to solve the difficulties in transferring enough heat from near walls to core mainstream at a heat flux of 5 MW/m2 in this paper. With the thermophysical properties near the supercritical point interpolated in the solver, flow structures and heat transfer performance in the cooling channels are obtained using a validated k-ω SST turbulence model. Effects of pitch ratios, channel materials and acceleration and buoyancy effects are also investigated in terms of the local bulk heat transfer coefficients, Fanning friction factors and entropy generation numbers by heat transfer and fluid flow. Overall, the existing of mini-ribs improves the heat transfer coefficient and reduces the entropy number by heat transfer at the cost of the increased fluid friction and the corresponding entropy number. Compared with the smooth channel, the overall enhanced factor can reach 1.73 with an overall thermal performance factor of 1.43 and the maximum wall temperature decreases by 27.57 % in the case of P/e = 10. When the solid channel material has higher thermal conductivity, it leads to a more uniform temperature distribution and lower entropy generation number by heat transfer with the enhanced transverse heat conduction within solid walls which also leads large heat transfer coefficients. Larger accelerations result in stronger heat transfer and larger fluid friction by strengthening the buoyancy effect which is more obvious when the state approach the critical point. This work provides a good reference for the application of supercritical CO2 in a regenerative cooling channel of scramjet engine at extremely high heat flux.

Numerical modeling and analysis of nanofluids subcooled boiling in a horizontal circular tube

Subcooled flow boiling, characterized by large heat transfer coefficient (HTC), is widely encountered and of great significance in energy industry. To enhance its thermal efficiency for compact applications, nanofluids are employed by improving the thermophysical properties. This article numerically investigates nanofluids subcooled boiling in a horizontal tube under wide-range, multi-factor impacts, including Reynolds number of 40,000–50,000, nanoparticle type, that is, Al2O3, TiO2, Cu, and volume fraction of 1%–5%. The thermal equilibrium assumption and Eulerian multiphase model are utilized after numerical validations. Results indicate that the vapor volume fraction augments along the tube while nanoparticles reduce the vapor production during boiling. As for thermal and flow performance, nanofluids can enhance the HTC at the expense of a rising pressure drop. In the case of Al2O3/Water nanofluid, the maximum of HTC increases by 10.56%. In contrast, the pressure drop increases by 2.1 times when the Al2O3 concentration changes from 1% to 5%. The performance evaluation criterion (PEC) in this article always exceeds 1 for nanofluids, demonstrating that the heat transfer enhancement outweighs the pressure drop penalty, and the Al2O3/Water nanofluid show superior performance with PEC achieving 1.1. This work can provide support for a profound understanding and utilization of nanofluids subcooled boiling.

Experimental and simulation study on oscillating flow and heat transfer characteristics of the cooling gallery in steel pistons

To characterize the oscillating flow and heat transfer characteristics of the cooling gallery inside a steel piston, a visual experimental platform was designed and constructed. Based on experimental results, simulation models of the cooling gallery under calibration conditions were established, and the oscillating flow and heat transfer characteristics of different oil injection strategies were studied. The results show that adjusting the nozzle diameter has a more significant impact on the fluid charge ratio (FCR) of the cooling gallery compared to the injection pressure. During the reciprocating motion of the steel piston inside the cylinder, the gallery has the largest heat transfer coefficient (HTC) on the Top wall at the top dead center (TDC) and the largest value on the Bottom wall at the bottom dead center (BDC). The average HTC of the Top wall is always the largest, followed by the Bottom wall, the In wall, and the Out wall being the smallest. Compared to the original design, the average HTC of the Top, Bottom, Out, and In walls can be increased by a maximum of 4.39 %, 3.96 %, 8.01 %, and 11.80 %, respectively.

On the continuous nature of phase change in near-critical carbon dioxide

Unique boiling behavior at near-critical conditions can leverage the large heat transfer coefficients associated with flow boiling while mitigating some of the disadvantages encountered in two-phase flows, presenting opportunities for enhancing the stability and effectiveness of cooling systems. Contemporary understanding treats subcritical boiling and supercritical heat transfer as two distinct regimes, separated by the critical point. Recent studies investigating microchannel flow boiling near the critical point challenge this notion, suggesting a significant alteration in subcritical phase change heat transfer mechanisms, predominantly driven by variations in thermophysical properties near the critical point. However, a generalized understanding of heat transfer behavior and the phase change physics near the critical point is lacking. The current work presents a new perspective to elucidate underlying fluid phenomena associated with near-critical (0.85<PR<1.02) microscale (Dh=500μm) phase change over parameterized experimental conditions (G=100−1000kgm−2s−1; q″=2−100Wcm−2). Through high-speed (8000fps) side-view microscopic imaging and simultaneous heat transfer measurements, unique flow behavior was discovered at PR>0.95, including supercritical-like phenomena and evidence of homogeneous nucleation which form the physical basis for altered heat transfer behavior. The visualized flow physics and heat transfer behavior suggest a continuous transition from subcritical phase change to supercritical mechanisms near the critical point. As homogeneous nucleation becomes the dominant phase change mechanism, the near-wall heat transfer condition transitions from nucleate boiling to single-phase vapor convection. However, due to significant thermophysical property variations near the critical point, this single-phase convection condition exhibits fluid physics and heat transfer behavior virtually indistinguishable from supercritical conditions. These insights significantly disrupt the conventional understanding of a sharp transition in fluid behavior at the critical point. The gradual change in flow boiling mechanisms near the critical point presents opportunities for application-specific tuning of heat transfer performance through pressure variation alone.

Thermal evaluation of heat exchanger and a dry-cooled supercritical CO2 mixture Brayton cycle based on three-dimensional and one-dimensional models: Key factors and potential applications

High ambient temperatures in the desert environment and heat capacity mismatch of printed circuit heat exchanger (PCHE) are always main factors that limited cycle efficiency of supercritical CO2 Brayton cycle (SCBC). The SCBC was established to obtain the operating parameters of precooler, low temperature recuperator (LTR) and high temperature recuperator (HTR) in this paper. The performance evaluation factors were developed and applied. The findings demonstrated that the precooler total heat transfer coefficient (HTC) peaked near the pseudo-critical temperature. Smaller hot-side pressure, larger hot-side and cold-side mass flux could improve heat transfer performance (HTP) of the precooler. The CO2-H2S in the precooler had larger HTC and pressure drop (ΔP), the CO2-Propane in the LTR and HTR had larger total HTCs and ΔP for the same critical temperature. Heat transfer correlations about the precooler of pure CO2 and CO2 mixtures were proposed. A conclusion was drawn by analyzing the performance evaluation factors that the PCHE using CO2-H2S for the precooler and CO2-Propane for the LTR and HTR could achieve better HTP under the same ΔP, but had the smaller effectiveness under the same ΔP. The CO2-H2S had the potential for practical application because of the larger cycle thermal efficiency and relatively good tolerance to the change of critical temperature.

Thermal and Visualisation Study of the HFE7100 Refrigerant Condensation Process

Abstract Technological advances are contributing to the search for highly efficient energy designs, and increasing interest in compact heat exchangers. Indeed, small channel diameters determine large heat transfer coefficients and condition a significant heat transfer area about the overall volume of the heat exchanger, as well as a smaller amount of refrigerant flowing in the system. Nevertheless, the operating stability and energy efficiency of compact heat exchangers are influenced by two-phase flow structures, which depend on thermal flow parameters. Knowledge of the structures formed during the condensation process is therefore essential for optimising the operation of refrigeration and air-conditioning equipment. This article presents the results from experimental studies of the HFE7100 refrigerant, from the hydrofluorocarbon group, condensation process in mini-channels with hydraulic diameters dh = 2.0 mm, 1.2 mm, 0.8 mm and 0.5 mm. Thermal flow characteristics were determined, and the forming structures of two-phase flow were recorded. The results of visualisation were subjected to morphological image analysis, based on a special algorithm written in MATLAB software. The algorithm makes it possible to determine the void fraction, which is necessary for calculating the vapour quality, as well as the area of vapour bubbles and their number, directionality and length along the x- and y-axes.

A comparative study of the impact on combustion and emission characteristics of nanoparticle‐based fuel additives in the internal combustion engine

AbstractThe search for an effective solution to improve performance and emission characteristics of internal combustion (IC) engines used in the commercial sector is regarded as one of the most important and essential issues in recent years due to increasing levels of pollution. Nanoparticles with their additive ability to increase fuel reactivity and atomization, due to their large surface area and high heat transfer coefficient, can improve the performance and emission characteristics of a fuel. This review highlights the use of nanoparticles as fuel additives to enhance the emission and performance characteristics of IC engines. Detailed comparisons of performance, emission, and combustion characteristics of IC engines using fuels blended with nanoparticles have been done. Nanoparticles were observed to be an oxygen buffer for fuel combustion and boost fuel atomization, thus enhancing engine performance. While alumina exhibited a decrease in levels of HC and CO but a considerable increase in NOx, graphene nanoparticles and ceria were found to be particularly effective in enhancing engine performance. Detailed study has been done on other nanoparticles, including metal‐oxide, nonmetal‐oxide as well as carbon nanoparticles. Overall, the use of nanoparticles can enhance the thermophysical characteristics of fuels, improving the emission and performance characteristics of engines. The review suggests that selecting the right dosage and variety of nanoparticles is crucial for optimizing engine performance, and thus directly helps in tackling the ongoing pollution problem.

Particle-scale simulation of air-blown gasification of biomass materials in bubbling fluidized bed reactor

Biomass gasification is a potential way for yielding product gases and energy, featuring by complex multi-physics and multi-phase flow. The multiphase particle-in-cell approach is adopted in the current study to investigate the behaviors of char, sand and biomass during biomass gasification in an air-blown bubbling fluidized bed. In the multiphase particle-in-cell method, particles are assumed adiabatic inside the body, and particles with identical properties are lumped into a parcel to reduce computational cost. The numerical model was well validated with experimental data. Some key conclusions can be drawn as: syngas has very similar but asymmetrical spatial distribution in the reactor due to the radially introduced raw biomass. Near the biomass inlet, biomass materials have large Reynolds number and heat transfer coefficient. Along the bed height, sand particles have largest heat transfer coefficient, followed by char and finally biomass. Enlarging bed temperature slightly increases the rising flux of biomass particles. This work emphasizes the significance of particle characteristics during biomass air gasification, and may supply useful guidance for industrial development and reactor design.

Effect of key structure and working condition parameters on a compact flat-evaporator loop heat pipe for chip cooling of data centers

Loop heat pipe has the advantages of large heat transfer coefficient without extra power input, therefore it has a good application potential in chip cooling of data centers. In this paper, a compact flat-evaporator loop heat pipe is designed and the effects of key structural parameters and working conditions on the dynamic and steady-state performance are studied. The results show that increasing heat load or the filling ratio, arranging vapor channels in the middle of the wick (rather than at the bottom) or lengthening the condenser can all reduce the temperature fluctuation; A small inclination angle of 5° and 10° can reduce the temperature fluctuation and the stable temperature, while large inclination angle of 15° will instead bring higher stable temperature; When the heat load increases step by step, the stable temperature (average temperature for fluctuation conditions) decreases and then increases for all filling ratios and structures; Minimized thermal resistance is achieved by optimizing wick and condenser structure under low and high heat load, respectively.

High-performance thermal management system for high-power LEDs based on double-nozzle spray cooling

Thermal management is one of the main challenges for high-power LEDs. As one of the state-of-the-art thermal management approaches, spray cooling can meet the requirements of fast cooling speed, large heat transfer coefficient, and less energy consumption when it provides thermal management for electronics with high heat flux. In this study, a high-performance spray cooling system for high-power LEDs is designed and established. The influence of nozzle configuration, flow rate, and nozzle-to-surface distance on the heat transfer characteristics are experimentally and numerically investigated. The system shows excellent heat dissipation capacity. Two different nozzle configurations are compared and the results show that the double-nozzle configuration possesses the highest single-phase heat transfer coefficient, reaching up to 20.7 kW/m2·K with the flow rate of 150 mL/min. Interestingly, double-nozzle, which owns better heat transfer performance compared to single-nozzle, shows worse temperature uniformity inside the testing module. Simultaneously, the junction temperature of double-nozzle at the center chip can also be controlled to 85 °C corresponding to a 10% reduction for single-nozzle. The proposed cooling system may enable the further application of spray cooling in electronics like high-power LEDs, potentially reducing the energy consumption in cooling electronics and promoting the utilization of low-grade thermal energy.

Optimization Turbine Blade Cooling by Applying Jet Impingement Cooling Channels

Abstract The aim of this paper is to optimize turbine blade cooling channels by applying jet impingement Method. The selection of experiment data for NASA 3CX turbine blade, and 3D model using solidworks software and create computational fluid dynamics (CFD) simulations used to model the coolant flow and temperature distribution in the vane, while experimental testing can validate the CFD results and provide additional insights into the cooling system's performance., ANSYS FLUENT code was used as a CFD solver, and ANSYS ICEM-CFD was used for mesh generation. MATLAB code is used for calculation using experiment data and this was helpful for simulations. Heat transfer conjugation analysis bases SST shear stress analyses K-ω turbulent model. The results conclude that providing additional information about the cooling channels and how they differ in the studies being compared. The results demonstrate that the cooling channels' hydraulic diameter decreases by a significant percentage (up to 49.70%–69.55%) as they are drawn to the trailing edge of the blade. This can have a significant impact on the heat transfer coefficients and the performance of the cooling system. The pressure side of the turbine blade is observed to follow the Hylton Model, while the current study predicts a large over-anticipated heat transfer coefficient around the Turbine blade head and on the bulk of the suction side. In terms of average heat transfer coefficient, the two models differ by 23.36%. The authors found that the cooling effectiveness for the Optimized jet impingement model is 0.4892 for whole blade and compared it with the cooling effectiveness for the optimized jet impingement model, which is 0.6936, The results of the comparison between the base model and the optimized jet impingement model suggest that the optimized model has a significantly higher cooling effectiveness. The increase in cooling effectiveness of 29.46% for the whole blade and 28.823% for the trailing edge indicates that the optimized jet impingement design provides improved cooling performance. These results highlight the importance of considering optimized cooling designs for turbine blades to maintain efficient and safe operation.

Investigation of sorption-enhanced hydrogen production by glycerol steam reforming in bubbling fluidized bed

Sorption-enhanced glycerol steam reforming process is numerically investigated by the multiphase particle-in-cell model within the Eulerian-Lagrangian framework in the bubbling fluidized bed with the aim of exploring the particle-level fundamentals of the binary particles. After the verification, the particle-scale evaluations and gas thermal properties are comprehensively presented. The results reveal that the size- and density-induced segregation results in the preferential distribution of CaO particles in the bottom zone of the bed. The particles in the bottom, freeboard, wake vortex and bubbling regions have a comparatively large heat transfer coefficient, velocity and slip velocity. At the same volume fraction, slip velocity and time instant, the heat transfer coefficient of sorbent is lower than that of catalyst. Increasing the superficial velocity elevates the heat transfer coefficient while reduces the C3H8O3 consumption and H2 yield. The probed results are of profound significance to the in-depth comprehension about complex gas–solid reacting flow and the process optimization of the sorption-enhanced hydrogen production system.

Numerical study of the intensification of single-phase heat transfer in a sandwich-like channel using staggered miniature-pin fins

This study presents the numerical analysis of single-phase forced convection heat transfer and pressure drop during internal flow in a shallow, rectangular sandwich-like copper channel heated from both the top and the bottom. Simulations were conducted using a commercial finite volume solver that solves governing continuity, momentum, and energy equations simultaneously. The bottom side of the channel was considered with arrays of rectangular miniature-pin fins. The miniature-pin fin geometry was modeled in a staggered configuration with tip clearance from the opposite surface while the orientation of the fins was directed parallel to the flow direction of the working fluid. Water was used as a working fluid with a fully developed velocity profile at the channel entry. Simulations were carried out for varying inlet temperatures and mass flow rates. All calculations were performed with the RNG k-ε model to model complex turbulent flows appropriately. Grid independence and validation analyses were also conducted. With the validated model, additional analyses were performed for 0, 0.1, 0.3, 0.6, and 1 mm tip clearances, and correlations were proposed after performing regression analyses for the friction factor and heat transfer coefficient. The calculations revealed that in contrast to a straight (nonfinned) surface, up to 220% larger heat transfer coefficients could be obtained for the finned surfaces under comparable operating conditions. It was also shown that tip clearance in turbulent flow affects heat transfer negatively. With increasing clearance, the Nusselt number decreased; in other words, heat transfer worsened. On the other hand, the use of miniature-pin fins led to a rise in the pressure drop over the entire heated length. For the Reynolds number spectrum of 4000–20000, the ratio of the friction coefficient of the finned surface to the friction coefficient of the nonfinned surface varied from 6 to 5 while with a further reduction in pressure loss a value of approximately 4 could be obtained for larger tip clearances. Hence, with larger tip clearances, the friction factor decreased, reflecting the abatement of pressure loss.

Analyzing the pressure and thermal efficiency of chemically synthesized nanofluids for computer cooling methods

To maintain ideal working conditions by removing heat, a particular technique must be applied. This research examines how nanofluids affect computer cooling microchannel heating devices. The experiment's working fluids are 25% Therminol-55 and 75% sprinkling water. The mixture contains silicon carbide (SiC), titanium oxide (TiO2), and zinc oxide (ZnO) nanoparticles. It includes 0.25% to 1.5% nanoparticles and flows at 0.025 to 0.080 kg/s at 25°C to 40°C. Central processing unit temperature, heat transfer rate, pressure losses, and pumping power have been examined. SiC-THERMINOL/SPRINKLING WATER at 1.5% concentration and 0.080 kg/s had a 9% lower temperature and 31% larger heat transfer coefficient than the base fluid. SiC-TL/SW has the highest pressure decrease and pumping force power compared to TiO2-TL/SW. Because nanofluid beats basic fluid in computer cooling, a little increase in pumping force power and pressure reduction may be tolerated.

Effect of water-cooling shock on fracture initiation and morphology of high-temperature granite: Application of hydraulic fracturing to enhanced geothermal systems

Deep geothermal energy exploitation is primarily accomplished using an enhanced geothermal system (EGS) to extract heat from hot dry rock (HDR). The use of hydraulic fracturing technology to build large-scale fracture networks is essential for improving the EGS heat extraction efficiency. Water-cooling shock on high-temperature rock degrades the mechanical properties of the rock while increasing the fracturing effect of HDR. A thermal–hydraulic–mechanical coupling model is proposed herein to investigate the effect of water-cooling shock on fracture initiation and morphology in HDR hydraulic fracturing. The validity of the coupling model is confirmed using theoretical analytical solutions and physical experimental results, such as hydraulic fracturing experiments on high-temperature granite, as well as analytical solutions for the stress shadow effect and fracture initiation pressure. The numerical simulation is performed using a coupling model to investigate the characteristics of fracture propagation and damage evolution during the HDR hydraulic fracturing process as well as to investigate the fracturing effect of water-cooling shock on high-temperature rock. Finally, the effects of initial rock temperature, in-situ stress, and heat transfer coefficient on fracture morphology are investigated. The results show that the combined effects of tensile strength deterioration water-cooling shock, thermal stress caused by cold shrinkage, and pore water pressure are primarily responsible for the initiation and propagation of hydraulic fractures. The water-cooling shock can considerably reduce the fracture initiation pressure, induce more secondary fractures, and form more complex fracture networks. The initial temperature and heat transfer coefficient of the rock affect the thermal stress and tensile strength deterioration. The formation of an intricate fracture network can be aided by a high initial rock temperature, a large surface heat transfer coefficient, and small in-situ stress differences.

Thermal analysis on the evaporation of fluid covered by porous media subjected to ultrasound and air jet impingement

The porous layer subjected to air jet is set above fluid passing through heating surface to control its thickness and avoid drying up, as well as ultrasound is introduced at upstream to enhance convection in flowing channel, in which heat flux can be dispersed in convection between fluid and heating surface as well as evaporation on the outside surface of porous cover to the outside. Local thermal equilibrium (LTE) occurs in porous cover, and the effect of sound pressure from ultrasound on liquid fluid is introduced according to acoustic theory. Brinkman–Forchheimer extended Darcy equations and k-ε turbulent model together with the above formulas are employed to describe the heat transfer in fluid covered by porous media subjected to ultrasound and air jet impingement. The effects of ultrasound power and frequency, fluid layer thickness as well as porosity and particle size in porous cover on heat transfer are investigated. The performance evaluation criteria (PEC) is defined to evaluate thermal characteristics in the cases with ultrasound than those without. The 35.7% rise ratio of heat transfer coefficient in the mode with ultrasound power of 50 W happens than that without. The higher ultrasound power and lower frequency of ultrasound cause lower heating surface temperature and larger heat transfer coefficient. The simulations agree with available published experiment data. All results of this study can be considered into utilization of ultrasound and porous layer to enhance heat transfer in flowing channel.

In‐silico vinyl chloride suspension polymerization: Kinetic modelling, thermal runaway prediction, and prevention

AbstractIn the present study, a combined kinetic and heat transfer model was developed to study the kinetics and predict thermal runaway of vinyl chloride (VC) suspension polymerization. Reactor temperature, monomer conversion, mole of initiator, radical concentrations in the two phases (i.e., VC‐rich phase and PVC‐rich phase), and average molecular properties were mapped during non‐isothermal processes. Meanwhile, the risk of thermal runaway was evaluated using S–Z (divergence) and H–J criteria. Simulation results show that a lower jacket temperature Tj and a larger heat transfer coefficient U are able to postpone or even avoid the risk of thermal runaway. Both of the criteria serve well for the prediction of thermal runaway during non‐isothermal processes. To prevent the occurrence of thermal runaway to the greatest extent, model‐based design of strategies for an isothermal polymerization process was done. Specifically, either jacket temperature Tj or heat transfer coefficient U can be fine‐tuned to maintain a 50°C isothermal process.

CFD investigation of the complex multiphase flow of biomass gasification in industrial-scale dual fluidized bed reactor

In this work, the process of biomass steam-gasification via a dual fluidized bed with a thermal input of 8MWth is numerically modeled by applying the multiphase particle-in-cell method. This model is successfully validated with the experimental data. Based on the simulation, the results can be epitomized as: distinct fluidization regimes in gasifier and combustor reactors give rise to different flow pattern and dispersion coefficients of solid phase in both reactors. Large particle heat transfer coefficients mainly appear in the upper regions of both reactors due to violent reactions. In this industrial-scale apparatus, the time-averaged heat transfer coefficient of sand in the combustor is larger than that of gasifier sand for about 40 W/(m2·K). Relationships between key variables such as volume fraction, heat transfer coefficient, slip velocity, Reynolds number and temperature of solid phase are discussed. Particles with small volume fraction tend to possess large heat transfer coefficient and slip velocity. The results explored at the particle-level might be useful in the industrial operating regarding the biomass steam-gasification processes.

Experimental and Numerical Analysis of the Influence of Microchannel Size and Structure on Boiling Heat Transfer

Computational fluid dynamics was used and a numerical simulation analysis of boiling heat transfer in microchannels with three depths and three cross-sectional profiles was conducted. The heat transfer coefficient and bubble generation process of three microchannel structures with a width of 80 μm and a depth of 40, 60, and 80 μm were compared during the boiling process, and the factors influencing bubble generation were studied. A visual test bench was built, and test substrates of different sizes were prepared using a micro-nano laser. During the test, the behavior characteristics of the bubbles on the boiling surface and the temperature change of the heated wall were collected with a high-speed camera and a temperature sensor. It was found that the microchannel with a depth of 80 μm had the largest heat transfer coefficient and shortest bubble growth period, the rectangular channel had a larger peak heat transfer coefficient and a lower frequency of bubble occurrence, while the V-shaped channel had the shortest growth period, i.e., the highest frequency of bubble occurrence, but its heat transfer coefficient was smaller than that of the rectangular channel.

Entropy generation analysis on thermo-hydraulic characteristics of microencapsulated phase change slurry in wavy microchannel with porous fins

• Combined design enables smaller temperature gradient and more uniform temperature. • Larger h m and lower ΔP can be concurrently gained in wavy MCHS with porous fins. • Thermal entropy is three orders of magnitude larger than the frictional entropy. • Thermal entropy increases with heat flux but the frictional entropy is opposite. • Lower irreversible losses can be achieved at the cost of higher power consumption. Recent advancement in micro/nano-scale electronic systems, the need for efficient heat dissipation has become more rigorous, and traditional thermal management solutions are facing enormous challenges. In this study, a novel combined design of wavy microchannel heat sink (MCHS) with porous fins and microencapsulated phase change material (MPCM) suspension is developed and numerically studied to achieve a balance between flow and heat transfer behaviors. The equivalent heat capacity method is adopted to deal with the phase change process of microcapsule particles in steady and laminar states, and the Brinkman–Darcy–Forchheimer model based on the volume-averaged method is employed to characterize the fluid flow in porous fins. A three-dimensional solid-fluid conjugate model is established based on the finite-volume method to investigate the effects of different coolant types (water and MPCM suspension), geometric parameters (wavy amplitude, wavelength, and channel width ratio), and working conditions (inlet flow velocity, heat flux, and slurry concentration) on the thermo-hydraulic properties and entropy generation of wavy MCHS. The results reveal that the combination of porous fins and MPCM suspension presents smaller temperature gradient and more uniform temperature distribution than conventional design. Larger heat transfer coefficient and lower pressure drop can be simultaneously obtained in wavy MCHS with porous fins than in solid fin configuration. The thermal entropy generation is three orders of magnitude larger than the frictional entropy generation, and the Bejan number is close to 1 for different microchannel configurations. Thermal entropy generation increases with increasing heat flux but the frictional entropy generation decreases. Lower irreversible losses can be achieved at the expense of greater pumping power consumption caused by increasing inlet velocity and suspension concentration. The superior effect of wavy MCHS with porous fins using MPCM suspension as coolant has been observed in all cases.