Thermal Fractionation Research Articles

Near Source Modeling of Pollutant Emissions From an Elevated Source Over an Urban Area Under Cross High Ventilation

Abstract Due to the rapid urbanization of many cities around the world, industrial manufacturing plants have grown rapidly, thus leading to the release of large amounts of pollutants into the environment. This is the main reason for the degradation of the local air quality, resulting in an increased risk of unfavorable sanitary conditions for city dwellers. Understanding the dispersion of pollutants in local population environments, meteorological conditions and other physical characteristics is fundamental for predicting and evaluating air quality. This paper provides comprehensive details on the study of flow patterns and pollutant dispersion processes in urban areas. Several factors which include building geometry, local atmospheric effects, structural obstructions, and velocity of exhaust pollutants are examined considering field data, wind tunnel tests, operational simulation techniques, and computational fluid dynamics. Good agreements are noticeable. Simultaneous evolutions of the velocity, thermal and scalar mass fraction fields of the pollutant emitting from a three-dimensional elevated source around a rectangular obstacle placed on a turbulent boundary layer wall, and also downstream the obstacle, have been successfully carried out. The most serious pollutant levels in urban areas under various high wind velocities are identified.

Disruption thermal load mitigation with shattered pellet injection on the Joint European Torus (JET)

Disruption mitigation remains a critical, unresolved challenge for ITER. To aid in addressing this challenge, a shattered pellet injection (SPI) system was installed on JET and experiments conducted at a range of thermal energy fractions and stored energies in excess of 7 MJ. The primary goals of these experiments were to investigate the efficacy of the SPI on JET and the ability of the plasma to assimilate multiple pellets. Single pellet injections produced a saturation in total radiated energy (W rad) with increasing injected neon content, suggesting total radiation of stored thermal energy. Further increases in injected neon quantities resulted in reduced cooling times and current quench (CQ) durations, indicating higher impurity assimilation. No significant variation in CQ duration or W rad was observed when varying the deuterium content at fixed neon quantities. Higher assimilation, inferred by shorter CQ durations, was measured when a mechanical punch was used to launch the pellets and this was attributed to a lower pellet velocity leading to higher solid content in the pellet plume and larger fragments penetrating deeper into the plasma. Radiation asymmetries averaged over the cooling time were inferred from Emis3D and ranged from 1.6 to 1.9. Asymmetries averaged over the entire disruption sequence were found to increase at higher thermal energy fractions. The radiated energy fractions decreased with increasing thermal energy fractions but this trend was eliminated when toroidal asymmetries were accounted for with Emis3D. Pure deuterium pellets were able to produce cooling times of up to 75 ms with a gradual loss in thermal stored energy of up to 80%. Experiments with multiple pellet injection indicated W rad can be increased through pellet superposition and density can be increased with an additional D2 injection without a reduction in W rad. KPRAD modelling accurately reproduced the cooling times and the CQ duration at high thermal energies. Assimilation estimates from KPRAD indicated CQ rates scale strongly whilst W rad scales weakly and saturates with assimilated neon content. Comparable W rad can be achieved with lower assimilated neon quantities as longer cooling times are attained. Thus reduced neon content can be preferential in a thermal load mitigation scheme as it may reduce radiation asymmetries and prevent flash melting.

Sensitivity of solar greenhouse envelopes to the thermal disfigurements and optimal selection of the thermal insulation quilt

The objectives of the present work are focused on exploration of the reasons for temperature difference in different envelopes, the sensitivity of envelopes of solar greenhouse to thermal disfigurements and optimal selection of the thermal insulation quilt. Theoretical analysis and derivation are conducted according to the experimental results of surface temperature, convective heat transfer, and heat flux density in different envelopes which with thermal disfigurements of solar greenhouse using heat transfer theory. The results revealed that the difference of intrinsic thermal conductivity and thickness of the envelopes leads to difference in the thermal flux and thus in the surface temperature of different envelopes. Compared with the front roof and back roof, the wall is more sensitive to thermal disfigurements. According to the influence of thermal disfigurements on solar greenhouse temperature, the allowable thermal disfigurements area fraction of front roof and back roof are given. Based on the analysis of heat transfer theory and test results, the work given the expression of the thickness and thermal conductivity of thermal insulation quilt under different outdoor minimum temperatures for optimal selection of thermal insulation quilt based on comprehensive considering factors of the solar greenhouse structure, crop demand, outdoor minimum temperature, and insulation quilt properties. The results of this work gives technical criterion for whether the envelopes with thermal disfigurements needs to be repaired or replaced, and it also provide theoretical and technical support for design the solar greenhouse as well as methodological guidance for the optimal selection of the thermal insulation quilt. Keywords: solar greenhouse, thermal disfigurements, optimal selection, thermal insulation quilt DOI: 10.25165/j.ijabe.20211405.6311 Citation: Sun Y C, Zhang Y, Zhu C M, Xu S N, Liu B W, Cao Y F, et al. Sensitivity of solar greenhouse envelopes to the thermal disfigurements and optimal selection of the thermal insulation quilt. Int J Agric & Biol Eng, 2021; 14(5): 50–55.

OPR1000 TI-SGTR 사고 MELCOR 해석의 자연순환유동 입력인자 생산을 위한 CFD 해석

We performed a 3-dimensional CFD analysis of a natural convective flow in the steam generator (SG) inlet plenum of an optimized power reactor 1000 MWe (OPR1000) to generate input parameters of the MELCOR code, a 1-dimensional lumped parameter code, which will be used in analyzing the temperature induced steam generator tube rupture (TI-SGTR) accident. The input parameters used in the MELCOR calculation will account for a 3-dimensional effect in the natural convective flow in the SG inlet plenum. To produce a credible CFD analysis result, we first established a CFD analysis methodology, which is developed from validation analyses against the steam generator design data of the OPR1000 and the Westinghouse 1/7 scaled-down test data, for the thermal mixing flow calculation between the SG and the reactor pressure vessel in the OPR1000. Though this CFD analysis, we produced the MELCOR input parameters, the recirculation ratio 1.96, thermal mixing fraction 0.79, discharge coefficient 0.13, and hot tube fraction 0.40, with an error range of approximately 10% to 25%. The input parameters will be used in the MELCOR analysis to evaluate a radioactive material release from broken SG tubes during the TI-SGTR accident.

Importance of shape factor in Sisko nanofluid flow considering gold nanoparticles

Nanofluids are extremely popular among researchers because of their high heat transfer rates which have major industrial applications. The foremost aim of the present work is to investigate the impact of thermal radiation in Sisko nanofluid flow with gold nanoparticles toward a stretching surface. The combined heat and mass transfer characteristics are investigated. Nanoparticles are used with blood as a base fluid. The suitable transformations are used to convert the governing PDEs into the nonlinear ODEs. The numerical solution of the nonlinear ODEs is obtained by using the bvp4c (Labotto IIIa) based shooting method. Moreover, flow predictions for each physical parameter are discussed. Physical reasons are used to illustrate the physical consequences of flow parameters versus perceived flow fields. The outcomes show that the velocity profile is declining function of velocity slip parameter. The temperature profile of the nanofluid is upgraded for both thermal radiation parameter and volume fraction of nanoparticles.

Investigation of the safety features of advanced PWR assembly using SiC, Zr, FeCrAl and SS-310 as cladding materials

In this work, SiC (Silicon carbide), FeCrAl (ferritic), SS-310 (stainless steel 310) and Zirconium are simulated by MCNPX (Monte Carlo N‐Particle eXtended) code as cladding materials in advanced PWR (Pressurized Water Reactor) assembly. A number of reactor safety parameters are evaluated for the candidate cladding materials as reactivity, cycle length, radial power distribution of fuel pellet, reactivity coefficients, spectral hardening, peaking factor, thermal neutron fraction and delayed neutron fraction. The neutron economy presented by Zr and SiC models is analyzed through the burnup calculations on the unit cell and assembly levels. The study also provided the geometric conditions of all cladding materials under consideration in terms of the relation between fuel enrichment and cladding thickness from the viewpoint to achieve the same discharge burnup as the Zircaloy cladding. It was found that the SiC model participated in extending the life cycle by 2.23% compared to Zr. The materials other than SiC largely decreased discharge burnup in comparison with Zircaloy. Furthermore, the claddings with lower capture cross-sections (SiC and Zr) exhibit higher relative fission power at the pellet periphery. The simulation also showed that using SiC with a thickness of 571.15 μm and 4.83% U-235 can satisfy the EOL irradiation value as Zr. For reactivity coefficient, the higher absorbing materials (SS-310 and FeCrAl) exhibit more negative FTCs, MTCs and VRCs at the BOL But, at the intermediate stages of burnup Zr and SiC have a strong trend of negative reactivity coefficients. Finally, the delayed neutron fraction of SiC and Zr models is the highest among all the four models.

NuSTAR and Swift observations of the extragalactic black hole X-ray binaries

ABSTRACT We present the results obtained from detailed spectral and timing studies of extragalactic black hole X-ray binaries LMC X–1 and LMC X–3, using simultaneous observations with Nuclear Spectroscopic Telescope Array (NuSTAR) and Neil Gehrels Swift observatories. The combined spectra in the 0.5–30 keV energy range, obtained between 2014 and 2019, are investigated for both sources. We do not find any noticeable variability in 0.5–30 keV light curves, with 0.1–10 Hz fractional rms estimated to be <2 per cent. No evidence of quasi-periodic oscillations is found in the power density spectra. The sources are found to be in the high soft state during the observations with disc temperature Tin ∼ 1 keV, photon index, Γ > 2.5 and thermal emission fraction, fdisc > 80 per cent. An Fe Kα emission line is detected in the spectra of LMC X–1, though no such feature is observed in the spectra of LMC X–3. From the spectral modelling, the spins of the black holes in LMC X–1 and LMC X–3 are estimated to be in the range of 0.92–0.95 and 0.19−0.29, respectively. The accretion efficiency is found to be, η ∼ 0.13 and η ∼ 0.04 for LMC X–1 and LMC X–3, respectively.

Thermal state of a conical antenna cooled by means of nanofluid saturated porous media

Thermal state of a conical antenna used for big data transfer was determined in this work. Its cooling is provided through porous media saturated with water-based copper nanofluid (NF) whose volume fraction varies in the 0% (pure water) [Formula: see text] range. Otherwise, the ratio between the thermal conductivity of the highly porous material and that of the fluid base (water) varies between 4 and 41.2. The solution is obtained by means of 3D numerical approach based on the volume control method using the SIMPLE algorithm in the large [Formula: see text]–[Formula: see text] Rayleigh number range. The average temperature of the antenna can be determined with the correlation proposed in this work for any combination of the thermal conductivity ratio, volume fraction and Rayleigh number. This new and original correlation makes it possible to determine the optimal values of these three influencing parameters to ensure the correct antenna’s operation.

Conjugate buoyant convective transport of nanofluids in an enclosed annular geometry

A vertical annular configuration with differently heated cylindrical surfaces and horizontal adiabatic boundaries is systematically studied in view to their industrial applications. In this paper, we investigate the effects of conjugate buoyant heat transport in water based nanofluids with different nanoparticles such as alumina, titania or copper, and is filled in the enclosed annular gap. The annulus space is formed by a thick inner cylinder having a uniform high temperature, an exterior cylindrical tube with a constant lower temperature, and thermally insulated upper and lower surfaces. By investigating heat transport for broad spectrum of Rayleigh number, solid wall thickness, thermal conductivity ratio and nanoparticle volume fraction, we found that the influence of wall thickness on thermal dissipation rate along wall and interface greatly depends on conductivity ratio and vice-versa. In particular, we uncover that the choice of nanoparticle in a nanofluid and its concentration are key factors in enhancing the thermal transport along the interface. Specially, copper based nanofluids produces higher heat transport among other nanoparticles, and for the range of nanoparticle concentration chosen in this analysis, enhanced thermal dissipation along the interface has been detected as nanoparticle volume fraction is increased. Our results are applicable to choose nanofluids along with other critical parameters for the desired heat transport.

Micro-scale prediction of effective thermal conductivity of CNT/Al composites by finite element method

Thermal conductivity of CNT/Al composites is considered to be an important property on composites design. However, the effect of microstructure on thermal conductivity has few been reported. In this study, a 3D multi-scale finite element model was developed to predict the effective thermal conductivity of CNT/Al composites, and the influences of CNT configuration, heat transfer direction, interfacial thermal resistance and volume fraction were investigated in detail. Five configurations of CNT were constructed including randomly arranged, evenly oriented, layered, bundled and networked. The results show that the CNT configuration plays a major role for the effective thermal conductivity of CNT/Al composites. The CNT/Al composite with layered configuration has the highest thermal conductivity, and when the volume fraction of CNTs is about 3.7 %, the CNT/Al composite displays an excellent effective thermal conductivity of 400 W/m·K, which increases about 84 % than that of the Al alloy. Moreover, the interface and thermal loading direction also have obvious effect on the thermal conductivity of the composites. The calculated results are in good agreement with experimental data existing in literature. The obtained findings in this study could provide a good theoretical basis for designing high thermal conductivity CNT/Al composites.

Insect processing for food and feed: A review of drying methods

Production of insects for food and feed purposes is rapidly emerging in Europe, filling an important niche of locally supplied protein and fat sources with improved environmental sustainability. Processing of insect biomass is becoming of utmost importance to fulfill the requirements for safe edible biomass and find efficient ways to reduce potential biological and chemical hazards. Current methods of insect biomass processing, well-developed, and established in food and feed industry, rely on thermal treatment (blanching, boiling, drying, cooling, freezing, freeze drying), mechanical (grinding, pressing, milling), and fractionation processes (extraction, purification, separation, centrifugation). This article summarizes and reviews recent activities performed by different interdisciplinary research groups dealing with insect drying. The diverse techniques for insect drying are discussed with the objective of identifying the ones with the highest economic, environmental, and social potential. Moreover, the quality attributes of insects dried with different methods (starting from simple sun drying and finishing with Pulsed Electric Fields enhanced lyophilization) are analyzed. Finally, selected legal aspects concerning usage of dried insects as food are presented.

Investigation of a Solar Polygeneration System for a Multi-Storey Residential Building-Dynamic Simulation and Performance Analysis

In the present study, the performance of a novel configuration of a solar polygeneration system for a multi-family residential building is investigated using dynamic simulation models. The system consists in Building Integrated PhotoVoltaic/Thermal (BIPVT) collectors, a water-to-water reversible heat pump and an adsorption chiller. The solar system will ensure space heating in winter, space cooling in summer and domestic hot water and electricity all over the year for a multi-storey building located in Algiers (Algeria). In the case of insufficient solar energy, the system is equipped with a gas-fired heater for auxiliary heat production, whereas the auxiliary electricity is supplied by the national grid. First, the simulation models of the solar system components and the building were described and developed in TRNSYS environment. Then, an energy-economic model based on the calculation of the primary energy consumption, the primary energy saving, the simple payback period and the electrical and thermal solar fractions, was carried-out. Finally, the system performance in terms of daily, monthly and yearly results was investigated and compared to the performance of a conventional energy system commonly used in Algerian buildings. The simulation results indicate that the solar collectors have the potential to cover more than 56% and 72% of the yearly heat and electricity requirements, respectively. The total primary energy saving achieved by the solar system with respect to the conventional one is 37.1 MWh/y, which represents 39% of the energy consumption of the conventional system. However, the economic feasibility of proposed solar system is difficult to be achieved due to the high initial cost of the solar collectors. Indeed, the obtained simple payback period is 55.40 years. Moreover, a sensitivity analysis has been performed aiming at studying the effect of various technical and economical parameters on the system performance. The analysis shows that the energetic as well as economic performances of the system are strongly influenced by the photovoltaic/thermal filed area, the system cost and the unitary cost of electricity. The system becomes economically profitable when the system cost is 400 €/m² and the electricity cost is 0.12 €/kWh. Additionally, the system performance is better in climate conditions where solar potential and building energy requirements are important.

Tailoring the thermal conductivity of functional cementitious composites with micro core-shell particles: A multiscale homogenization study

Micro core-shell particles have been highlighted in developing energy-efficient functional cementitious composites (FCCs). In this paper, a multiscale model is established to predict the thermal property of cementitious matrices containing micro core-shell particles. Based on the composite material theory, the interfacial thermal conductance and inclusion size distribution are introduced to the Mori-Tanaka homogenization scheme. Following the scale division of FCCs, the effective thermal conductivity is homogenized step by step from the cement paste level to micro-encapsulated cementitious composites level. In what follows, the coupling effects of composition, microstructural and physical aspects are quantified through the model parametrization. As validated by experimental results, accurate numerical predictions can be obtained with the variations of w/c ratio, hydration degree, and mix proportion. Numerical parameter analysis further reveals that the thermal conductivity and volume fractions of composition phases dominate the maximum thermal design range of FCCs, while the size-dependent interfacial thermal conductance matters more when the thermal conductivity of shell material is lower than that of the core material. The findings provide a theoretical basis for the thermal design of multi-phase composites, and contribute to the rational utilization of micro particles to achieve desirable thermal properties of FCCs.

Numerical study of melting and heat transfer of PCM in a rectangular cavity with bilateral flow boundary conditions

The melting of phase change material (PCM) in a rectangular cavity with heat transfer fluids (HTFs) flowing at both sides from bottom up (bilateral flow boundary conditions) are numerically studied. A parametric study is performed by changing the Reynolds number (Re) of HTF in a range of 1 × 104, 3 × 104, 5 × 104, 7 × 104 and the Rayleigh number (Ra) in a range of 3 × 106, 4 × 106, 5 × 106, 6 × 106. The results show that the formation of natural convection is due to the impacts of non-uniform heat transfer of HTF and cooling between solid-liquid interface and liquid PCM. The asymmetric flow boundaries lead to various skew forms of the PCM melting process and effect the heat transfer and thermal energy storage. The melting process can be divided into three melting stages, the first two stages are mainly ruled by Re and the last stage by Ra. A set of introduced dimensionless parameters are analyzed to elaborate the heat transfer mechanism and the general rule of melting characteristics. The various dimensionless correlations are applied to describe the evolution of melting volume fraction, dimensionless average temperature and thermal energy storage fraction during the melting process.

MHD heat and mass flow of nano-fluid over a non-linear permeable stretching sheet

In this study, we examine the Magneto-hydrodynamics (MHD) heat and mass flow of nano-fluid over a non-linearly permeable stretching sheet. The resulting partial differential equations are converted to a system of ordinary differential equations using the similarity transformation and solved numerically using shooting technique with fourth order Runge-Kutta method. The effect of some fluid parameters on the momentum, thermal and nanoparticle volume fraction boundary layers were expatiated for prescribed surface temperature and constant surface temperature through graphs. An excellent agreement was found when the results obtained in this study were compared with results in previous literature.

Optical Activity in Saturated Cyclic Amines: Untangling the Roles of Nitrogen-Inversion and Ring-Puckering Dynamics.

The dispersive optical activity of two saturated cyclic amines, (R)-2-methylpyrrolidine (R-2MPY) and (S)-2-methylpiperidine (S-2MPI), has been interrogated under isolated and solvated conditions to elucidate the roles of large-amplitude motion associated with nitrogen-center inversion and ring-puckering dynamics. Experimental optical rotatory dispersion profiles were almost mirror images of one another and displayed parallel solvent dependencies. Quantum-chemical analyses built on density-functional and coupled-cluster methods revealed four low-lying conformers for each molecule, which are distinguished by axial/equatorial orientations of their amino hydrogens and methyl substituents. Chiroptical signatures predicted for these species were combined through an independent-conformer ansatz to simulate the ensemble-averaged response, with a polarizable continuum model (PCM) being used to treat implicit solute-solvent interactions. The intrinsic behavior observed for isolated (gaseous) R-2MPY and S-2MPI was reproduced best by merging coupled-cluster (CCSD) estimates of rotatory powers with thermal population fractions deduced from complete basis set (CBS-APNO) free-energy calculations. Although prior claims of sizable chiroptical contributions arising from helically twisted (chiral) heterocyclic frameworks could be discounted, less satisfactory agreement between experiment and theory was realized for solution phases. Response properties sustained modest isomer-dependent changes in the presence of PCM solvation, but the corresponding energy metrics showed systematic trends, whereby structures having larger electric-dipole moments were stabilized preferentially in media of high polarity. Despite the fact that R-2MPY conformations were predicted to undergo a progressive reordering of their relative energies across the six solvents of interest, S-2MPI was found to exhibit more pronounced solvent-induced perturbations at long wavelengths (viz., in regions far removed from electronic resonances). Experimental results are discussed in terms of the distinct ring-puckering mechanisms for R-2MPY and S-2MPI, which are expected to be dominated by hindered pseudorotation among envelope/twist motifs and semi-inversion between chairlike antipodes, respectively.

Adaptiveness of a model predictive controller for a thermal-electrical renewable energy system in four different German single-family house energy standards

Model predictive controller (MPC) until now is required to be custom designed for each particular case. A combined system-level controller and universalization of MPC is yet to be achieved. This article focuses on simulatively investigating the adaptability of a previously developed whitebox-model MPC using a generic objective function for increasing renewable energy fraction and self-consumption in a decentralized integrated renewable energy system. The chosen single-family house energy standards are: high renewable fraction house (Sonnenhaus); modern building (KfW55); low primary energy house (passive house); and old building from 1995 (WSchVO95). From the perspective of universal implementation, it could be identified that a change in weightage factors is only required for the old WSchVO95 building. An astonishing reduction in space heating demand: 15% for Sonnenhaus; −30% for KfW55; −30% for passive house; and −2% for WSchVO95 could be accomplished. In terms of energy supply, ca. 10% increase in solar thermal fraction with the new buildings and a 14% increase in PV supply in all buildings could be achieved. Altogether, decentralized system self-consumption fraction increases by 8–12% via MPC. Whitebox MPC is however still a hindrance with huge optimization time making it not suitable for real-time implementation.

Multiblock Copolymers of Norbornene and Cyclododecene: Chain Structure and Properties.

We investigate the structure–property relations of the multiblock copolymers of norbornene with cyclododecene synthesized via the macromolecular cross-metathesis reaction between amorphous polynorbornene and semicrystalline polydodecenamer in the presence of the first-generation Grubbs catalyst. By adjusting the reaction time, catalyst amount, and composition of the initial system, we obtain a set of statistical multiblock copolymers that differ in the composition and average length of norbornene and dodecenylene unit sequences. Structural, thermal, and mechanical characterization of the copolymers with NMR, XRD, DSC (including thermal fractionation by successive self-nucleation and annealing), and rotational rheology allows us to relate the reaction conditions to the average length of crystallizable unit sequences, thicknesses of corresponding lamellas, and temperatures of their melting. We demonstrate that isolated dodecenylene units can be incorporated into crystalline lamellas so that even nearly random copolymers should retain crystallinity. Weak high-temperature endotherms observed in the multiblock copolymers of norbornene with cyclododecene and other cycloolefins could indicate that the corresponding systems are microphase-separated in the melt state.

Numerical Investigation of Anisotropic Conductivity of Date Palm Fiber Bundle Composite

Date palm fiber bundle includes lumens in solid region, which present low thermal conductivity than that of fiber bundle. In this work, the transverse thermal conductivity of date palm fiber bundle was determined by numerical software to investigate the relation between the bundle fiber and the solid region thermophysical properties. Therefore, the results determined from the numerical investigation were compared to the analytical model to prove the numerical model developed in this study. In this context, numerical simulation of thermal conductivity was performed by the numerical finite element method by COMSOL software. To verify the developed models, the bundle fiber and solid region thermal conductivity relation were determined. Quadratic and Cubic polynomial expressions, were used to study the influence of the normalized conductivity of the bundle fiber and the solid region of the composite material and to evaluate the composites thermal conductivity. Influence of lumen on the thermal conductivity was also investigated in this work. The results indicate that the bundle fiber thermal conductivity is much less than that of the solid region thermal conductivity. This one depends on pore dimension, but not on distribution and shape of pore. The numerical results obtained from the model developed in this study are compared with analytical model to validate this model. Finally, a sensitivity analysis was conducted with the models to investigate how changes in the values of important variables, such as thermal conductivity and volume fraction of the constituent, can affect the effective thermal properties of the composite.

COLDz: Deep 34 GHz Continuum Observations and Free–Free Emission in High-redshift Star-forming Galaxies

Abstract The high-frequency radio sky has historically remained largely unexplored due to the typical faintness of sources in this regime, and the modest survey speed compared to observations at lower frequencies. However, high-frequency radio surveys offer an invaluable tracer of high-redshift star formation, as they directly target the faint radio free–free emission. We present deep continuum observations at 34 GHz in the COSMOS and GOODS-North fields from the Karl G. Jansky Very Large Array (VLA), as part of the COLDz survey. The deep COSMOS mosaic spans down to σ = 1.3 μJy beam−1, while the wider GOODS-N observations cover to σ = 5.3 μJy beam−1. We detect a total of 18 galaxies at 34 GHz, of which nine show radio emission consistent with being powered by star formation; although for two sources, this is likely due to thermal emission from dust. Utilizing deep ancillary radio data at 1.4, 3, 5, and 10 GHz, we decompose the spectra of the remaining seven star-forming galaxies into their synchrotron and thermal free–free components, and find typical thermal fractions and synchrotron spectral indices comparable to those observed in local star-forming galaxies. We further determine free–free star formation rates (SFRs), and show that these are in agreement with SFRs from spectral energy distribution-fitting and the far-infrared/radio correlation. Our observations place strong constraints on the high-frequency radio emission in typical galaxies at high redshift, and provide some of the first insights into what is set to become a key area of study with future radio facilities, such as the Square Kilometer Array Phase 1 and next-generation VLA.