Glycol-water Mixture Research Articles

Dynamical behaviour of magneto-copper-titania/water-ethylene glycol stream inside a gyrating channel

Inspired by the latest deeds of nanomaterials and their novel features in science and engineering sectors, a detailed mathematical model is presented to investigate an unsteady magneto-buoyancy-driven flow of a non-Newtonian (Casson model) chemically bonded hybrid nano liquid (copper-titania/water-ethylene glycol mixture) streaming through a gyrating channel with fluctuating wall temperature and concentration confined by the porous regime. Hybridized nanoparticles (copper-titania) are dispersed into the water-ethylene glycol mixture (vol.60–40%) hybrid base Casson liquid. Hall currents, porous resistance, thermal radiation, and Dufour impacts are hypothesized in the flow system. This model’s governing partial differential equations are derived from the generic laws of conservation of momentum, energy, and mass. These derived equations are rendered dimensionless by incorporating the normalization variables and parameters. The solutions of the dimensionless transport equations are realized in the closed-form followed by an analytical approach. The stipulated graphs and tables are designed to scrutinize the physical and theoretical upshots of a variety of essential system parameters on the critical dynamical functions or variables. Our simulation results based on set parameters disclose that Hall currents have a propensity to accelerate the fluid flow in the vertical direction and lessen the magnitude of the fluid velocity along the cross-flow direction. Amplifying frequency parameter recommends a diminution in the temperature and concentration profiles. The pattern of streamlines, heatlines, and masslines is drawn to envisage the flow and transport features in the gyrating channel. The novelty of this thermal model is that significance of rotating hybrid suspension and dominating magnetic field along with Hall currents is identified. Due to the rotation of the system, the flow is noticeably amended by the centrifugal and Coriolis forces. The present model is, of course, of great practical and technological importance, for example, chemical engineering, material science, mineral and cleaning oils manufacturing, and plastic and polymer industries.

Down the Dimensionality Lane: Thermal Conductivity Enhancement in Carbon-Based Liquid Dispersions.

Carbon allotropes of different dimensionality, i.e., 1D-carbon nanotubes, 2D-graphene nanoplatelets, and 3D-graphite, possess high thermal conductivity (TC > 2000 W/m K). They are, therefore, excellent candidates for filler material aiming at increasing the TC of composites used for thermal management. However, preparing aqueous dispersions of these materials is challenging due to their strong van der Waals attraction, leading to aggregation and subsequent precipitation. Reported dispersion methodologies have failed to disperse large microscale fillers, which are essential for efficient thermal management. In this work, we suggest to "kinetically arrest" the dispersion by using sepiolite, a fiberlike clay, that effectively disperses all three carbon dimensionalities. We explore the effect of filler dimensionality and properties (lateral size, thickness, defect density) on the dispersion TC enhancement. Modeling the TC by the effective medium approach allows lumping all the intrinsic properties of the filler into a single parameter termed "effective TC", providing an accurate prediction of the experimentally measured TC. We show that, by judicious choice of filler, the TC of both water and a water-ethylene glycol mixture can be enhanced by 31% using graphene nanoplatelets of 15 μm in lateral size. We believe that the guidelines obtained in this work provide a useful tool for designing future liquid composites with enhanced thermal properties.

Investigation of Heat Transfer Properties of Water-ethylene Glycol Mixture and some Commercial Coolants

Heat transfer properties of water, ethylene glycol and two commercial coolants in Nigerian markets (Abro and Holt) were studied by observing the effect of various aqueous mixtures of the respective fluid on boiling point, elevation of boiling point and relative density. The results obtained from the study indicated that ethylene glycol has the best heat transfer capacity due to its molecular properties and high ebuloscopic constant (15.38). The performance of ethylene glycol and the commercial coolants was found to increase with increase concentration. The present study gives insight on the design of better heat transfer fluid and the optimum fluid to water ratio that could ensure best performance.

Performance Performance Analysis of Tubular PEM Fuel Cell Models and Thermal Analysis of Base Model using Ethylene Glycol-Water Mixture as a Coolant

Abstract: This work aims towards the simulation of Various proton exchange membrane fuel cell (PEMFC) models to investigate the effects of operating parameters such as temperature, pressure, anode flow levels and cathode reactants, component types, cooling temperatures in the performance of a modified fuel cell. The basic model and the tubular model are developed in modelling software based on the size of the parameter later simulated using the addon module in the Ansys software. The Addon module is specifically designed to mimic a different type of fuel cell. The simulated model of cell power output showed positive compliance with experimental results taken from the literature and revealed that the operating pressure, temperature, and flow rate of reactants positively affect the function of the Fuel cell. The results also showed that the cooling temperature of the coolant indicates higher concentrations of current congestion compared to the base model without cooling. Corrective results obtained from the effect of temperature on cell function showed that the fuel cell temperature favor both cell function and efficiency. It can therefore be assumed that the efficiency of the cell is strongly influenced by operating temperature, pressure, cooling temperature, fuel flow rate and oxidant. Keywords: PEM fuel cell, Current density, tubular fuel cell, addon-module.

Thermal effectiveness of solar collector using Graphene nanostructures suspended in ethylene glycol–water mixtures

Flat plate solar collectors (FPSCs) are the most often used as solar collectors due to their easiness of installation and usage. The current research investigates the energy efficiency of FPSC using different mass concentration with varied base fluids containing Graphene nanofluids (T-Gr). Mass concentration of 0.1%-wt., 0.075%-wt., 0.050%-wt. and 0.025%-wt. were mixed with ethylene glycol (EG) and distilled water (DW) in different rations. The operating conditions were volumetric flowrate (1.5, 1 and 0.5) LPM 50 °C-input fluid temperature and 800 W/m2-global solar irradiation. Scanning electron microscope (SEM) and energy dispersive X-ray (EDX) were used to synthesize the thermally treated nanomaterial. The theoretical investigation indicated that using T-Gr nanosuspensions increased the FPSC efficiency in comparison with the host fluid for all examined mass concentrations and volumetric flowrates. In quantitative terms, the maximum thermal effectiveness improvement for the EG, (DW:70 + EG:30) and DW:EG (DW:50 + EG:50) and using flowrates of (1.5, 1 and 0.5) LPM were 12.54%, 12.46% and 12.48%. In addition, the research results pointed that the essential parameters (i.e., loss energy (FRUL)) and gain energy (FR (τα)) of the T-Gr nanofluids were increased significantly.

Heat transfer studies of Al2O3/water-ethylene glycol nanofluid using factorial design analysis

The experimental study of the heat transfer coefficient of nanofluid plays a significant role in improving the heat transfer rate of the heat exchanger. A natural convection apparatus was used to study heat transfer in the suspension of Al2O3 nanoparticles in a water-ethylene glycol mixture base fluid. The effects of the heat input, the nanoparticle volume fraction, and the base fluid concentration on the heat transfer coefficient were studied using a 23 full factorial design matrix (16 experimental runs) and the MINITAB Design software. The levels for the heat input, nanoparticle volume fraction, and base fluid concentration were 10 and 100 W, 0.1 and 1 vol.%, and 30 and 50 vol.%, respectively. The residual, contour, 3D surface plots, and Pareto chart were drawn from the experimental results. The observed heat transfer coefficient showed the highest enhancement with the high level of the nanoparticle volume fraction and a moderate enhancement with the high level of heat input, and a slight enhancement with the base fluid concentration.

Binary mixture droplet wetting on micro-structure decorated surfaces

Liquid surface tension as well as solid structure play a paramount role on the intimate wetting and non-wetting regimes and interactions between liquids droplets and solid substrates. We hypothesise that the coupling of these two variables, independently addressed in the past, eventually offer a wider range of understanding to the surface science and interfacial communities.In this work, intrinsically hydrophobic micro-pillared surfaces varying in the spacing between structures, and pure ethanol, pure water and their binary mixtures (as well as acetone–water and ethylene glycol–water mixtures) are utilised, accessing a wide range of substrate solid fractions and liquid surface tensions experimentally. Wettability measurements are carried out at different azimuthal directions to exemplify the wetting/non-wetting behaviour as well as the droplet asymmetry function of both liquid composition and structure spacing.Our findings reveal that high water concentration droplets, i.e., high surface tension fluids, sit in the Cassie-Baxter regime while partial non-wetting Wenzel or mixed-mode regimes with enhanced droplet asymmetry ensuing for medium and high ethanol concentrations, i.e., low surface tension fluids, below certain micropillar spacing. Beyond micropillar spacing s ≥ 40 µm, the impact of the surface structure on the droplet shape is negligible, and droplets adopt a similar contact angle and circular shape as on a flat smooth hydrophobic surface. Wetting and non-wetting regimes are then supported by classical wetting theories and equations. A wetting regime map for a wide range of surface tension fluids and/or their mixtures on a wide domain of solid fractions is then proposed.

The influence of temperature on physical properties of a hybrid nanofluid flow in a non-Darcy porous medium

The purpose of this paper is to debate the influences of variable thermal conductivity as well as viscosity on a hybrid nanofluid flow through a non-Darcy porous medium along a wavy surface. Two kinds of base fluids are considered; the first is water (H2O) with [Formula: see text] and the second is ethylene glycol–water mixture (C2H6O[Formula: see text]H2O) with [Formula: see text]. Furthermore, the physical properties of the base fluid have been modified via the addition of two kinds of suspended nanoparticles. The suspended nanoparticles of alumina Al2O3were firstly added to the base fluid. Then, titania TiO2suspended nanoparticles are immersed into this nanofluid to form two hybrid nanofluids (TiO[Formula: see text]Al2O3/H2O) and (TiO2-Al2O3/C2H6O2–H2O). Dupuit Forchheimer model as a non-Darcy porous medium is utilized. The mathematical model for the present physical problem with convective boundary condition is studied numerically via the Chebyshev pseudospectral (CPS) technique. Nusselt number, velocity and temperature profiles are investigated under different parameters. The present outcomes clarify that adding the alumina nanoparticle supports and improves the efficiency of the titania nanoparticle. Also, taking both of the hybrid nanofluid viscosity/thermal conductivity as variable functions of temperature has an important role to support the studies of heat transfer.

Comparison of Heat Transfer rates for Water and Ethylene Glycol mixtures for Diesel engine exhaust gas heat recovery using Shell and Tube Heat Exchanger.

Most of the researchers have claimed that high compression engines (diesel engines) are performing slightly above of 1/3rd of their potential and remaining heat energy is wasted in the form of exhaust gas. Efforts are going on to improve the design of these engines and investigations are being carried out to recover this waste energy from exhaust gases and utilize for different applications.In the present work, initially water is used as a heat exchange medium for three different loads on diesel engine viz., 50%, 60% and 70%, which extracts heat energy to evaluate the exhaust heat attainable from exhaust gases of the engine. The exhaust gas is passed through the tube side of the heat exchanger which is obtained from an exhaust manifold of a four stroke single cylinder diesel engine. Water is passed through the shell side of the shell and tube heat exchanger. Later this work is repeated for two different cooling medium i.e. water-ethylene glycol mixtures with 25% and 50%. The results are compared for 60% engine load conditions. The counter flow type heat exchanger arrangement is considered for the analysis. The temperatures were recorded for hot gases and cold medium at inlet and outlet points of the shell side and tube side flow. Heat calculations are carried out for each combination and detailed in the result–discussion and conclusion chapter. The objective of this work is to assess the exhaust gas heat recovery capacity using the ethylene glycol-water mixture and come out with a mixture for higher heat recovery capacity. This work is undertaken with segmental baffle heat exchanger of zero degree inclination. Also the work is repeated for inclined baffle heat exchangers of 10-degree and 20-degree baffle inclination to assess the effectiveness of liquid in recovering the heat from exhaust gases. It is observed that the water and Ethylene glycol mixtures have performed satisfactorily in all three baffle setups showing only 1.5% - 2.0% less heat recovery when compared with only water.

Precise determination of R134a boiling bundle effect on a column of reentrant cavity tubes

The boiling bundle effect was investigated on a column of reentrant cavity tubes to reveal the heat transfer coefficient (HTC) variation for a tube which is affected by other tubes. All experimental data were obtained on the specific tube, which is the distinct difference between the adopted homologous method and the routine method. Two columns of eight horizontal tubes were submerged in R134a liquid, and each tube was specifically heated by an ethylene glycol–water mixture. The saturation temperature was 6.0 °C, the heat flux ranged from 10.0 kW/m2 to 28.0 kW/m2, and the row number ranged from 1 to 7. The tube length in the test section was 500 mm, and the pitch–diameter ratio was 1.32. Results showed that the uncertainty of the bundle effect using the homologous method was less than ± 4.4%, which decreased by at least 80% compared with that using the routine method. The values were from 1 to 1.32, indicating that the upward bubbles from the lower heated tubes positively influenced the boiling HTC. Moreover, the bundle effect increased with the increase in row number and decreased with the increase in heat flux. Correlations of the single-tube HTC and the bundle effect with vapor film Reynolds number and effective row number were established to predict the experimental data. The current study can offer a reference for further investigations of film or convective boiling on tube bundles.

Experimental and Numerical Study of Thermal Performance for Flat Plate Solar Water Heater in Najaf

This work presented the numerical and experimental study of the thermal performance of a flat plate collector (FPC). This study focuses on analyzing the performance of (FPC) in the climatic conditions of Najaf and calculating the thermal energy produced by the collector for domestic use, which reduces the electricity consumption that Iraq is witnessing a severe shortage in its supply. Also, various working fluids (water, oil engine, ethylene glycol-water mixture) were tested to determine the best working fluid that improves the collector’s efficiency. The experiments were performed in Najaf, Iraq (32° 2’ N / 44° 18’ E) on January 9, 2019. The simulation study of the (FPC) is performed by COMSOL Multiphasic 5.3 software. The numerical results were validated with experimental results and there was good convergence between them. The results showed that the average daily efficiency of the solar collector (FPC) was 37.17%, and the highest outlet water temperature of the collector was 57.1Co. The collector achieved a useful cumulative useful heat during the day of about 3.3557 MW, this contributes to reducing the use of electricity and achieving the required economic feasibility of use (FPC). Finally, the engine oil gave better results in improving efficiency compared to other working fluids.

Ceramic 3-D Printed Direct Winding Heat Exchangers for Thermal Management of Concentrated Winding Electric Machines

Direct cooling of the windings in a motor using oil offers more effective thermal management than conventional alternatives and can therefore increase the torque density of electric machines; however, this technique is limited by the thermophysical properties of the oil. The use of a direct winding heat exchanger allows a glycol-water coolant mixture to be used, which leads to a significant improvement in heat transfer and a reduction in the pumping losses compared to direct oil cooling. This article proposes ceramic 3-D printed direct winding heat exchangers (3D-DWHX), which can significantly improve the cooling of windings in electric machines due to the unique geometries enabled by 3-D printing. Ceramics are also capable of withstanding extremely high temperatures, which extends the application of the proposed 3D-DWHX. A closed-form analytical thermal model incorporating the temperature dependence of winding losses is proposed and used with empirical heat transfer correlations to design a microfeature enhanced 3D-DWHX. The ceramic 3D-DWHX was built and tested in a motorette that demonstrated a continuous current density of 35.7 A <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RMS</sub> /mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , corresponding to a continuous specific power in the reference electric machine of at least 12.1 kW/kg while keeping the maximum winding temperature below 200 °C.

On the definition of excess electrical conductivity

It is proposed that the complex electrical conductivity of an ideal fluid liquid mixture is expressed as the sum of pure-component complex electrical conductivities weighted by their volume fractions in the mixture. The relevance of the corresponding excess property in the investigation of enhanced electrical conductivity of nanofluids is highlighted for the case where the base fluid consists of ethylene glycol–water mixtures. New measurements of the direct current conductivity were made for these mixtures at 298.15 K. It is pointed out that different published experimental measurements lead to excess electrical conductivity values with opposite signal. These discrepancies are discussed and possible explanations advanced. The proposed analysis of electrical conductivity is adapted to binary systems of nanofluid-base fluid and, using literature data, the usefulness of excess electrical conductivity is demonstrated.

Rod-like Ni0.5Co0.5C2O4·2H2O in-situ formed on rGO by an interface induced engineering: Extraordinary rate and cycle performance as an anode in lithium-ion and sodium-ion half/full cells

Transition metal oxalates have attracted wide attention due to the characteristics of the conversion reaction as anode materials in lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), However, there are huge volume expansion and sluggish circulation dynamics during the reversible Li+ and Na+ insertion/extraction process, which would lead to unsatisfactory reversible capacity and stability. In order to solve these problems, a rod-like structure Ni0.5Co0.5C2O4·2H2O is in-situ formed on the reduced graphene oxide layer (Ni0.5Co0.5C2O4·2H2O/rGO) in a glycol–water mixture medium via an interface induced engineering strategy. Benefitting from the synergistic cooperation of nano-diameter rod-like structure and high conductive rGO networks, the experimental results show that the prepared Ni0.5Co0.5C2O4·2H2O/rGO electrode has predominant rate performance and ultra-long cycle stability. For the LIBs, it not only exhibits an ultrahigh reversible capacity (1179.9 mA h g−1 at 0.5 A g−1 after 300 cycles), but also presents outstanding rate and cycling performance (646.5 mA h g−1 at 5 A g−1 after 1200 cycles). Besides, the Ni0.5Co0.5C2O4·2H2O/rGO electrode displays remarkable sodium storage capacity of 221.6 mA h g−1 after 100 cycles at 0.5 A g−1. Further, the extraordinary electrochemical capability of Ni0.5Co0.5C2O4·2H2O/rGO active material is also reflected in two full-cells, assembled using commercial LiCoO2 as cathode for LIBs and commercial Na3V2(PO4)3 as cathode for SIBs, both of which can show wonderful specific capacity and cycling stability. It is found in in-situ Raman experiments that the reversible changes of oxalate peaks are monitored in a charge/discharge process, which is scientific evidence for the transform reaction mechanism of metal oxalates in LIBs. These findings not only provide important ideas for studying the charge/discharge storage mechanism but also give scientific basis for the design of high-performance electrode materials.

Применение наножидкостей в качестве теплоносителя в охладителях функциональных агрегатов автотракторной техники

One of the most important elements of the cooling system of any automotive internal combustion engine is a coolant. Most often, water and a mixture of water with antifreeze are used as a coolant. Its main function is to transfer heat or to cool the engine. Nanofluids are promising heat carriers, with the help of which it is possible to reduce the metal consumption of aggregates, increase safety in emergency transient modes accompanied by boiling. (Research purpose) The research purpose is studying the possibilities, features and prospects of using innovative heat carriers as coolants of automotive equipment, which will allow overcoming the inefficiency of water and ethylene glycol mixtures, which consists in low thermal conductivity. (Materials and methods) Nanofluids consisting of a base liquid and nanoparticles of a highly heat-conducting material were proposed as innovative heat carriers. Their use in transport power plant coolers will reduce their volume and weight. Mixing of ethylene glycol and copper nanoparticles is effective, in such cases it is important to investigate the effect of the volume fraction of copper nanoparticles and the base liquid on thermal characteristics or to reduce the size of the radiator. Copper nanoparticles have better thermal conductivity than other nanoparticles (for example, aluminum oxide). (Results and discussion) It has been proved that the use of nanofluids in heating and ventilation systems can give a significant increase in heat transfer. At present the science of nanofluids is in its initial stage, for the development of this direction it is necessary to conduct comprehensive experimental studies of their chemical and physical properties, theoretical analysis, and compilation of general calculated correlations. (Conclusions) It was revealed that nanofluids can be effectively used as heat carriers of transport engines, with their use the metal consumption of coolers is reduced, the safety of units in emergency modes, including those accompanied by boiling, is increased.

BİR ISI DEĞİŞTİRİCİSİNDE FARKLI SU-ETİLEN GLİKOL KARIŞIMI KULLANIMININ ISI TRANSFER PERFORMANSINA ETKİLERİNİN DENEYSEL ANALİZİ

In this study, the effects of using different water-ethylene glycol mixture rates on heat transfer performance put in an automobile radiator as a liquid is experimentally analysed. Ethylene glycol is added in water volumetrically and experiments are conducted for 0%, 25%, 50%, 75% and 100% volumetric ratio of ethylene glycol. For all these mixture rates, 300 experiments are conducted for fluid inlet temperature between 40-80 °C, fluid inlet flow rate between 10-22 l/min and cooling air between 1-4 m/s. As a result of the experiments, it is observed that as ethylene glycol mixture ratio passing from the radiator increased, heat transfer decreased. However, as cooling air velocity, fluid inlet flow rate and radiator inlet temperature increased, heat transfer increased as well. When water-ethylene glycol mixture is used in the radiator instead of water, it is observed that radiator fluid freezing temperature decrease and radiator heat transfer performance is negatively impacted.

Energy Analysis of Concentrated Photovoltaic/Thermal Panels with Nanofluids

In this study, a prototype system was established for location heating application and electricity generation through utilizing two concentrated photovoltaic thermal panels (CPV/T) possessing flat surface receivers connected in series with each other. The purpose of the system is to supply the heating needs of a room in winter season and to meet the electricity requirement of the equipment used in this system. In the analysis of the installed system, different refrigerants (10% mono propylene glycol + 90% water and 0.5% Al2O3-water nanofluid) were tested at three different flow rates (0.4 m3/h, 0.5 m3/h, 0.6 m3/h). Throughout the experiments, the fan-coil air outlet temperature used to heat the room was adjusted to 35 °C with an inverter and a process control device. The results attained from the experiments carried out using different fluids throughout different months and days (April-May) have demonstrated that the thermal and electrical efficiencies of the system are found to be in good agreement with each other when evaluated in terms of the fluids utilized. The highest electrical energy recovery was found as 268 W at 0.6 m3/h flow rate for propylene glycol-water mixture and 194 W at 0.5 m3/h flow rate for nanomixture. The total thermal energy efficiency for the system using different fluids was found to be around 22%. The total thermal energy gain of the system was also calculated as 2312 W at 0.6 m3/h for the propylene glycol mixture and 2041 W at 0.5 m3/h for the nanomixture.

Performance Comparison of Propylene Glycol-Water and Ethylene Glycol-Water Mixtures as Engine Coolants in a Flat-Tube Automobile Radiator

This study aims at evaluating and comparing the thermal performance of five different engine coolants employed in an experimental engine cooling system with a flat-tube louvered-fin automobile radiator. For this purpose, a PLC-controlled test system was set up. The system could maintain the temperatures of the air and coolant at the radiator inlet, the speed of the air and flow rate of the coolant at the required values during the tests. The tested coolants were pure wa-ter, 30/70 ethylene glycol (EG)/water, 30/70 propylene glycol (PG)/water, 50/50 EG/water and 50/50 PG/water mixtures. In all tests, the coolant temperature at the radiator inlet was kept at 90°C, while the coolant flow rate was varied between 0.10–0.25 l/s with 0.05 l/s increments. Furthermore, the air temperature at the ra-diator inlet was kept at 25, 30 and 35°C, and the air speed passing over the radia-tor was varied between 1–4 m/s with 1 m/s increments. The thermal performance of the radiator was evaluated by locating the measured coolant flow rate and coolant inlet/outlet temperatures into the conservation of energy equation. It was found that water yielded the highest radiator heat rejection rates. Compared with water, 30/70 EG/water, 50/50 EG/water, 30/70 PG/water, 50/50 PG/water mix-tures yielded on average 3.50%, 7.89%, 8.28%, 11.46% lower radiator heat rejec-tion rates, respectively. Since PG has some advantages over EG such as lower cost and toxicity, PG mixtures can be employed as antifreeze instead of EG mix-tures in expense of a slight decrease in the thermal performance.

Effect of Solvent on Protonation Equilibria of L-Serine and L-Tryptophan in Ethylene Glycol-Water Mixtures

Protonation equilibria of L-serine and L-tryptophan in varying compositions (0.0-50.0 % v/v) of ethylene glycol-water mixtures were investigated pH-metrically. Titrations were performed at 303.0 K and the ionic strength of the medium was maintained at 0.16 mol L-1 using sodium chloride. The protonation constants have been calculated with the computer program MINIQUAD 75 and are selected based on statistical parameters. The best fit chemical models of the protonation equilibria were based on crystallographic R-factor, χ2, skewness and kurtosis. The protonation constants of L-serine and L-tryptophan change linearly with increasing ethylene glycol content. This is attributed to the dielectric constant of the medium.

Heat Transfer Enhancement of Single-Phase Internal Flows using Shape Optimization and Additively Manufactured Flow Structures

• We optimize the shape of internal fins using generative design. • The optimized fins are additively manufactured from alsi10 mg. • Rigorous measurements and simulations characterize heat transfer performance. • The optimized fins have 65–77% lower thermal resistance than conventional designs. This paper reports heat transfer enhancement of forced internal single-phase flow enabled by additively manufactured internally finned channels. We consider internal liquid coolant flow through a tube with constant heat flux applied to the exterior surface. A genetic algorithm was developed and used to optimize the fin geometry in order to minimize total thermal resistance for laminar flow or convection thermal resistance for turbulent flow. The genetic algorithm sampled more than 500 fin geometries, evaluated thermal resistance, and selected the optimum fin geometry. We selected three designs for experimental testing: a complex fin structure suggested by the genetic algorithm; a straight fin design; and a smooth circular channel as a reference. The devices were made from aluminum silica (AlSi10Mg) using direct metal laser sintering additive manufacturing. The devices were tested using a water ethylene glycol mixture (80:20) over the hydraulic diameter based Reynolds number range of 400 – 18,000, covering both laminar and turbulent flow regimes. Finite element simulations of heat transfer and pressure drop helped to understand and interpret the measurements. Compared to the smooth pipe reference design, the total thermal resistance of the genetically optimized fin design was 77% lower for laminar flow at Re h = 2,000 and 65% lower for turbulent flow at Re h = 10,000. Compared to the straight fin design that is commonly used for enhancing convection heat transfer in internal flows, the total thermal resistance of the genetically optimized fin design was 55% lower for laminar flow at Re h = 2,000 and 29% lower for turbulent flow at Re h = 10,000. We explore the potential design space for different types of heat exchangers by investigating how total heat transfer varies with exterior heat transfer coefficient and channel wall thermal conductivity. This research shows how shape optimization and additive manufacturing can result in devices with improved internal convection heat transfer.