Heat Flux Type Research Articles

Investigation on the thermal control and performance of PCM–porous media-integrated heat sink systems: Deep neural network modelling employing experimental correlations

Phase change material (PCM)-based heat sinks can offer reliable and effective thermal management (TM) solutions for increasingly sophisticated applications. A critical aspect of such heat sinks is determining how long it takes them to reach a set-point temperature. However, no generalised method exists in the literature that can predict and interpret the thermal performance of a wide range of PCM–porous media-integrated heat sinks. In this regard, this study examines the heat transfer characteristics of PCM-based heat sinks integrated with various metallic foams through experimental and deep learning (DL) techniques. The experiments are performed for transient TM analysis of various PCM-based heat sinks. Diverse variables, including foam porosity (0.95–0.97), PCM fraction (0.6–0.8), heat flux (0.8–2.4 kW/m2), foam materials (Fe–Ni alloy, Ni and copper) and PCM type (RT-35HC, RT-44HC, RT-54HC and paraffin wax), are investigated in this study. The experimental data are fed to the optimal DL model using the Bayesian surrogate model-tuned hyperparameters. Utilising a correlation analysis, as exemplified by the heat map and correlation plot, in conjunction with explainable artificial intelligence, it has been deduced that the thermal performance of the heat sink is principally influenced by factors such as PCM type, PCM fraction, foam material, foam porosity, and heat flux. Comparing the model's predicted data with the empirical findings, a good agreement was observed. Specifically, the mean absolute error (MAE) for the anticipated temperature and gradient registered at 0.0438 and 0.0054, whilst the mean square error (MSE) manifested values of 0.0579 and 0.0087, respectively. The proposed model can accurately assess the heat sink's thermal performance (correlation coefficient, R2 = 0.99) for various PCM types, fractions, foam materials, applied heat flux and foam porosity.

The role of plasma–atom and molecule interactions on power & particle balance during detachment on the MAST Upgrade Super-X divertor

This paper shows first quantitative analysis of the detachment processes in the MAST Upgrade Super-X divertor (SXD). We identify an unprecedented impact of plasma-molecular interactions involving molecular ions (likely D2+ ), resulting in strong ion sinks (Molecular Activated Recombination—MAR), leading to a reduction of ion target flux. The MAR ion sinks exceed the divertor ion sources before electron-ion recombination (EIR) starts to occur, suggesting that significant ionisation occurs outside of the divertor chamber. In the EIR region, Te≪0.2 eV is observed and MAR remains significant in these deep detached phases. The total ion sink strength demonstrates the capability for particle (ion) exhaust in the Super-X Configuration. Molecular Activated Dissociation is the dominant volumetric neutral atom creation process can lead to an electron cooling of 20% of PSOL . The measured total radiative power losses in the divertor chamber are consistent with inferred hydrogenic radiative power losses. This suggests that intrinsic divertor impurity radiation, despite the carbon walls, is minor in the divertor chamber. This contrasts previous TCV results, which may be associated with enhanced plasma-neutral interactions and reduced chemical erosion in the detached, tightly baffled SXD. The above observations have also been observed in higher heat flux (narrower SOL width) type I ELMy H-mode discharges. This provides evidence that the characterisation in this paper may be general.

Performance of printed circuit heat exchangers in SCO2 Brayton/Organic Rankine combined cycle: Assessment of simplified boiling temperature and heat flux type of boundary conditions

In this study, a simplified boiling temperature type of boundary condition (BTBC) is developed and used to study the performance of printed circuit heat exchanger (PCHE) with semicircular channels. CFD is used to simulate both fluid and heat flows in PCHE semicircular channels are used as a precooler in a combined supercritical CO2 Brayton/Organic Rankine cycle. Based on local heat transfer and flow characteristics of SCO2, the results of BTBC are compared to heat flux type of boundary condition (HFBC). The classical (Gnielinski) correlation and the modified heat transfer correlation (modified Jackson) which are frequently used to capture the heat transfer behavior of SCO2 are quantitatively evaluated for the two types of boundary conditions. The results show that the junction of different temperature sections of PCHE has the greatest influence on heat transfer coefficients, and the flow from the overheated section into the evaporation section accelerates the increase of heat transfer coefficients and enables them to reach their peak values faster. It is also found that the buoyance influence along the flow direction is significant and different for the two tested boundary conditions. In addition, results show that BTBC have bigger effects on the heat transfer coefficient at the different junctions of the precooler, compared to HFBC. Also, compared to the CFD results using BTBc, more than 90% of the data points predicted by the modified Jackson correlation are predicted within + 35% and −15% error margin, which is a better matching compared to the predictions of Gnielinski correlation. This type of boundary conditions can have a great influence on heat transfer of SCO2, and thus it is necessary to adopt a more accurate boiling model to capture well the coupled heat transfer between SCO2 and the organic working medium.

CONVECTIVE CATTANEO-CHRISTOV HEAT FLUX AND HEAT GENERATION EFFECT ON MHD WILLIAMSON FLUID FLOW OVER AN EXPONENTIALLY STRETCHING SURFACE WITH THERMAL RADIATION

The two-dimensional steady incompressible MHD boundary layer flow of convective Williamson fluid flow of the Cattaneo-Christov heat flux type over an exponentially stretching surface in the presence of heat generation and thermal radiation is considered. The nonlinear governing partial differential equations are reduced to ordinary differential equations by using a similarity transformation. The Homotopy Analysis Method (HAM) is applied to solve the reduced equations and the effects of importanceof fluid parameters are explained through graphs. Also, the HAM solutions were compared with the numerical solutions and good agreement was observed

Analysis of phase change material thermal effects in large-scale proton-exchange membrane fuel cell based on open-source computational fluid dynamics

In recent years, solid–liquid phase change materials (PCM) have been used in various applications for thermal management. However, PCM thermal effects on proton-exchange membrane fuel cells (PEMFC) have not been investigated. In this study, the effects of PCMs on the thermal management of a PEMFC are evaluated using a novel 3D model based on an open-source computational fluid dynamics (CFD) software. In addition, metallic bipolar plates have been considered for this study. The results indicate that when the cooling system is turned off, PCMs can have a good cooling effect for more than 120 s. It is also observed that the temperature of the PCM-equipped model is uniform, contrary to the non-PCM model. Two types of boundary conditions, uniform and non-uniform heat flux, have been considered for this study. The results suggest that if PCM is embedded in anode section, non-uniform heat flux distribution leads to better thermal performance, whereas if PCM embedded in cathode section or in non-PCM design, it is the opposite. Moreover, it is figured out if PCM is located in cathode section, co-direction flows of coolant and reactants lead to lower thermal performance, while it is contrary for other designs. It is also demonstrated that the PCM can store a significant amount of waste heat.

Thermal analysis of simultaneously evolving laminar pulsatile flow through two large parallel plates with time-dependent heat flux boundary conditions

Understanding unsteady convective heat transfer (UCHT) behavior of simultaneously evolving laminar pulsatile flow between two large parallel plates exposed to time-dependent thermal boundary conditions is the goal of this research. The time-dependent sinusoidal velocity waveform is applied at the entrance of the two large parallel plates exposed to time-dependent sinusoidal heat flux boundary conditions (TSHBC). The finite volume technique is used in the present work. The current results have been compared to the literature data under the same operating conditions and found to be in good concurrence. The influence of various parameters, for instance, amplitude, frequency, phase difference, heat flux ratio, and the Reynolds number on the transient Nusselt number, is investigated. An improvement in energy transfer is observed when the pulsatile flow between two large parallel plates with TSHBC than the non-pulsatile flow with a fixed heat flux type boundary. Furthermore, the energy transfer improvement is observed once the velocity and heat flux waveform frequency is equal. The applicability of the present work could be found in the solar heating system, cooling of electronic devices, etc., whereby a more robust understanding of the unsteady convective heat transfer could facilitate the design and develop an efficient system.

The effect of ribs spacing on heat transfer in rectangular channels under the effect of different types of heat flux in the Presence of a nanofluids

In this study, numerical computations of the influence of adding ribs in a rectangular channel on the forced convection heat transfer and laminar fluid flow characteristics has been carried out. The analysis was carried out by using the finite element method to solve the dimensionless governing equations for two-dimensional channel with 80 mm height and 2000 mm length at the Reynolds number of (10, 100, and 500), rib height e=8mm with different aspect ratios (AR =2.5, 3.125, 3.75, 4.375, and 5). Also, the study compared two cases of investigations with and without nanofluid (Water/ TiO2) at the volume fractions of nanoparticles of 0, 2 and 4%. The results concluded that, for a certain arrangements, the use of extended surfaces within a rectangular channel can significantly enhance the rate of heat transfer and when the aspect ratios decreases, the Nusselt number increased. However, the existence of ribs within channel in case of constant heat flux can cause a significant improvement of heat transfer compared to that in the corresponding channel under the variable heat flux.

Boiling Heat Transfer for Aqueous Surfactants Solutions on Flat Surface (Dept.M)

Experimental study for boiling heat transfer over a flat surface was achieved by using aqueous surfactants solutions and compared wi1h pure water. An experimental lest loop equipped with the required measuring devices was designed and constructed to assess the effects of surfactants type , concentration of aqueous surfactants solutions, and the applied heat flux on the boiling heat transfer process. The tested surfactants are Polyvinyl Alcohol (nonionic surfactant) and Sodium Laury] Sulfate (anionic surfactant). Concentrations of aqueous surfactant solutions varied in this work from zero up to 3000 ppm and the applied heat flux from 15300 to 31230 W/m2. The experimental measurements of temperature, pressure and volume flow rate are recorded and manipulated to calculate the boiling heat transfer coefficient and the enhancement factor the boiling heat transfer coefficient. The obtained experimental results showed that, the wall temperature of flat surface was reduced for the same heat flux by using aqueous surfactants solutions compared with pure water. Accordingly, the boiling heat transfer coefficient increased when using aqueous surfactants solutions and increased also with increasing heat flux in the range of the. studied operating parameters. The enhancement factor of the boiling heat transfer coefficient reached to a maximum value with concentration 20 ppm for Polyvinyl Alcohol and concentration 30 ppm for Sodium Lauryl Sulfate , and then it decreased with increasing concentrations. The enhancement facto r for the tested surfactants solutions in this work relative to the pure water is found to be 1,08 La 1.3 depending upon type of surfactants, its concentration and wall heat flux . This improvement in the boiling heat transfer coefficient characterized by a reduction in the bubble departure diameter, increased departure frequency , reduction in the coalescence and increased in the number of nucleation sites. Comparison with the previous work gave good agreement.

Single-phase natural circulation in a rectangular loop with a finite capacity heat sink positioned below the heater section

One of the passive safety systems employed in nuclear reactors is a large water pool positioned at an elevation, which acts as a heat sink to remove decay heat from the reactor core in the event of an accident using the natural circulation phenomena. A large mass of water at an elevated position has concerns regarding the safety of support structure, and therefore an alternative methodology where the heat sink is positioned just below the heater section is investigated in this study. Results of an experimental and numerical investigation for the thermal-hydraulic behavior of single-phase natural circulation in a rectangular loop of height 4300 mm and width 1900 mm with the heat sink located at an elevation just below the heater section is reported here. The heat sink was a finite one, a constant volume insulated tank filled with water, whereas the heat source was a constant heat flux type. The loop was constructed with circular pipe elements with a nominal inner diameter equal to 40 mm. The heater section was 1m in height and three input power values equal to 1.15 kW, 1.55 kW, and 2 kW were used in the study. The flow behavior in a single and twin parallel heater system with a single riser was studied. The loop fluid is initially in a single-phase and becomes two-phase as the heat sink temperature rises, but only the results for the loop fluid in the single-phase regime are presented in the current study. The measured mass flow rate, after an initial transient, settles down to values which slowly decreases with time. The average temperature of the heat sink is shown to rise continuously with increasing time, demonstrating the effectiveness of the heat sink in removing the energy input to the working fluid in the heater section. However, the heat sink removes only 60–70% of the input heat while the rest is either lost to the ambient or utilized to raise the enthalpy of the working fluid.The Nusselt numbers in the heater section are also presented which steadily rise after an initial transient. In addition, the values are much higher than those for the corresponding Reynolds number values in forced convection due to the influence of buoyancy-induced convection. The Nusselt number is well correlated by the expression Nu‾=1.35(Ra*‾)0.3 for 2×105≤Ra*‾≤6.5×105and 600≤Re≤1000. Numerical predictions for loop flow rate, temperature variation, and sink temperature using the RELAP5/MOD3.2 code for the experimental configuration of the current study are presented which compare well with the measurements the maximum deviation being less than 10%. Numerical results for pressurizing the working fluid and permitting boiling in the heat sink to drive the system towards steady-state operation are also presented.

Pressure Influence on the Thermophysical Properties of 316L Austenitic Stainless Steels Manufactured By Powder Metallurgy Method

Austenitic stainless steel that is used in the industrial areas such as automotive has high physical and mechanical properties. In this study; thermophysical properties of 316L austenitic stainless steel prepared by powder metallurgy method that is attracted for researchers due to obtain net or near shaped product and complex shaped materials, have been investigated. Austenitic stainless steels pressed on the 400 and 600MPa pressures and pressed austenitic stainless steel samples sintered at 1200 °C temperature for an hour under inert gas atmosphere. The thermophysical features o these sintered austenitic stainless steel were performed at temperature ranging from RT to 600 °C via heat flux type Differential Scanning Calorimeter (DSC). These properties supported by SEM images, EDS spectrums and OM (Optic microscope) images.

Experimental and computational inverse thermal analysis of transient, non-linear heat flux in circular pin fin with temperature-dependent thermal properties

The functional form of the heat flux for three different profiles namely constant,Φ=0.98; using (q=VIt/A), linear-triangular and non-linear realistic under static and dynamic conditions are retrieved with the aid of inverse analysis based on the GSSM for a pin fin (length =0.35 m, cross-section area = 7.85×10-5 m2) with all temperature-dependent parameters. The forward model is solved using pdepe solver (dτ=0.4167, dξ=0.1429). The recovered heat flux is in good agreement with its expected profile. The acceptable measurement errors are 5%, 3% and 4% with errors of 3.72%, 6% and 4% under static conditions and 4%, 2% and 2% with errors of 11%, 9.6% and 14% under dynamics condition for constant, triangular and realistic profile type of heat flux respectively. Furthermore, experiments are conducted and the functional heat flux has been retrieved for experimental data. The two retrieved heat fluxes follow similar trends. The effect of the measurement errors in the input temperature upon the exactitude of the retrieved heat flux is also studied. The present procedure is useful in designing heat flux meters for a variety of thermal applications.

A setup for studies of laminar flame under microwave irradiation.

Plasma assisted combustion is a very active research field due to the potential of using the technology to improve combustion efficiency and decrease pollutant emission by stabilizing lean burning flames. It has been shown in a number of studies that a small amount of electrical energy can be deposited in the flame by applying microwaves, resulting in enhanced flame propagation and thus improved flame stabilization and delayed lean blow-out. However, the effects have not yet been properly quantified since there are significant experimental challenges related to the determination of both the laminar burning velocity and the electric field strength. In the present work, a novel setup is described, where a well-defined burner system is coupled to a microwave cavity. The burner is of heat flux type, where a flat laminar flame is stabilized on a perforated burner head. The advantage of this burner for the current use is that the method and related uncertainties are well studied and quantified, and the geometry is suitable for coupling with the microwave cavity. The setup, experimental procedure, and data analysis are described in detail in this article. Laminar burning velocity for a methane-air flame at ϕ = 0.7 is determined to certify that the burner works properly in the microwave cavity. The flame is then exposed to pulsed microwaves at 1 kHz with a pulse duration of 50 µs. The laminar burning velocity at these conditions is determined to be 18.4 cm/s, which is an increase by about 12% compared to the laminar burning velocity that is measured without microwave exposure. The setup shows potential for further investigations of lean flames subjected to various microwave pulse sequences. The data are of high quality with well-defined uncertainties and are therefore suitable to use for validation of chemical kinetics models.

Phase-Lag Effects in Skin Tissue During Transient Heating

A three-phase-lag (TPL) model is proposed to describe heat transfer in a finite domain skin tissue with temperature dependent metabolic heat generation. The Laplace transform method is applied to solve the problem. Three special types of heat flux are applied to the boundary of skin tissue for thermal therapeutic applications. The depth of tissue is influenced by the different oscillation heat flux. The comparison between the TPL and dual-phase-lag (DPL) models is analyzed and the effects of phase lag parameters (<i>τq</i>, <i>τt</i> and <i>τv</i>) and material (<i>k</i><sup>*</sup>) on the tissue temperature distribution are presented graphically.

Determination of thermodynamic properties of the ternary oxides in the Y-Ru-O system by electromotive force measurements and differential scanning calorimetric measurements

In this study, the standard molar Gibbs energy of formation of Y2Ru2O7(s) and Y3RuO7(s) was determined using calcia-stabilized zirconia (CSZ) as an electrolyte and air as a reference electrode. The cells can be represented by: (−)Pt/{Y2O3(s) + Y2Ru2O7(s) + Ru(s)}//CSZ//O2(p(O2) = 21.21 kPa)/Pt(+), (−)Pt/{Y3RuO7(s) + Y2Ru2O7(s) + Y2O3(s)}//CSZ//O2(p(O2) = 21.21kPa)/Pt(+). The electromotive force was measured in the temperature range from 981 to 1155 K and 932 to 1186 K, respectively. The standard molar Gibbs energy of formation of Y2Ru2O7(s) and Y3RuO7(s) from elements in their standard state was calculated by the least squares regression analysis of the data obtained in the present study and can be given, respectively, by: {ΔfG(Y2Ru2O7, s)/(kJmol−1) ± 2.22} = − 2554.1 + 0.625 ⋅ (T/K) and {ΔfG(Y3RuO7, s)/(kJmol−1) ± 2.45} = − 3249.5 + 0.635 ⋅ (T/K). The standard molar heat capacity Cop,m(T) of Y2Ru2O7(s) was measured using a heat flux–type differential scanning calorimeter (DSC) in the temperature range, from 307 to 780 K. The heat capacity was fitted into a mathematical expression and can be represented by: Cp, m(Y2Ru2O7, s, T)(JK−1mol−1) = 256.1 + 5.88 ∙ 10−2T(K) − 34.75 ∙ 105/T2(K). (307 ≤ T (K) ≤ 780). The heat capacity of Y2Ru2O7(s) was used along with the data obtained from the electrochemical cell to determine its decomposition temperature and stability in air and to calculate other thermodynamic parameters.

Effect of side wall conditions and aspect ratio on convective pattern formation in Rayleigh-Benard convection

Effect of side wall boundary conditions and aspect ratio in very small boxes on patterns formed during Raleigh-Benard (RB) convection is studied using an indigenously developed flow solver based on the finite difference method. While keeping the bottom (hot) and top (cold) walls isothermal, the side wall thermal conditions are kept either constant heat flux or isothermal type. For constant heat flux side wall condition, the considered value of heat flux lies between 0 and maximum corresponding to conductive heat flux between top and bottom walls. For isothermal side wall condition, the chosen value of temperature is between the top and bottom wall temperatures. The computational domain is a cube or a square prism with aspect ratio in longitudinal direction (ARx) varied between 1.2 and 2 in steps of 0.2. For fixed value of ARx = 1.6, aspect ratio in transverse direction (ARz) has been varied for adiabatic side wall conditions. Effect of side wall condition on orientation of roll axis and the number of rolls has been investigated with observations well supported by stream traces and temperature contours. Moreover, for selected parameters, based on nature of pattern formation for steady flow, onset of oscillatory convection is explained.

Stability of the pyrochlore Tm2Ru2O7(s) & comparison of its stability with other heavy rare earth ruthenium pyrochlores

The Gibbs energy of formation of Tm2Ru2O7(s) has been determined employing a solid-state electrochemical cell incorporating an oxide ion conducting electrolyte. The reversible electromotive force (e.m.f.) of the following cell was measured:Cell : (−)Pt/{Tm2O3(s) + Tm2Ru2O7(s) + Ru(s)}//CSZ//O2(p(O2) = 21.21kPa)/Pt(+)The standard molar Gibbs energy of formation of Tm2Ru2O7(s) from elements in their standard state, calculated by the least squares regression analysis of the data obtained in the present study, can be given by:{ΔfG°(Tm2Ru2O7,s)/(kJ · mol−1) ± 1.9} = − 2511.9 + 0.625 ⋅ (T/K); (977 ≤ T/K ≤ 1265).Standard molar heat capacity Cop,m(T) of Tm2Ru2O7(s), was measured using a heat flux type differential scanning calorimeter (DSC) in two different temperature ranges, from 128 K to 276 K and 307 K to 686 K. The heat capacity in the higher temperature range was fitted into a mathematical expression and can be represented by:C°p,mTm2Ru2O7sT)(J⋅K−1·mol−1=297.8+2.0⋅10−3TK−62.1⋅105/T2K.307≤TK≤686The standard molar heat capacity data of Tm2Ru2O7(s), along with the data obtained from the oxide electrochemical cell were used to calculate the standard enthalpy of formation and absolute molar entropy of the compound. The standard Gibbs energy of formation obtained earlier for other heavy rare earth ruthenium pyrochlores were compared with the present results.

Differential scanning calorimetric measurements and thermodynamic functions of YbRhO3(s)

Abstract

Natural convection heat transfer characteristics of molten salt with internal heat generation

Molten salt is a promising heat transfer fluid with its high heat capacity, high boiling point, and chemical stability. In liquid fueled molten salt reactors and spent fuel reprocessing unit, molten salt carries heat generating fuel itself in a liquid state. To investigate the natural convection heat transfer performance of molten salt, a vertical heater vertical cooler rectangular loop filled with chloride salt containing liquid fuel, NaCl-KCl-(Pu, 238U)Cl3, is simulated using an open source CFD package, OpenFOAM under various heat input conditions; external heat flux, internal heat generation (IHG), and a combined heat input type condition. Different aspects of natural convection heat transfer according to heat input condition are found for same amount of total heat. The external heat flux condition generates a high temperature gradient near the heater wall with very thin thermal boundary layer due to the low thermal conductivity of molten salt. On the other hand, the IHG condition has a relatively flat temperature profile from its uniform volumetric heating. Due to the different behaviors of temperature evolution, local upward flow is formed only at the wall region under the heat flux condition, but global natural circulation flow is promoted under IHG condition. The combined type condition is largely dependent on how much heat exists in heat flux type, which strongly influences local heat and fluid phenomena in natural convection heat transfer. Molten salt has a high dependence on the heat input condition from its thermo-physical properties. Therefore, the distinct characteristics of molten salt and heat input conditions should be considered, when designing and analyzing the molten salt systems with both external and internal heating conditions.

Pyrolysis kinetics of Hibiscus rosa sinensis and Nerium oleander

ABSTRACTPyrolysis is a thermal method in which volatile matter present in a biomass will be degraded to lower molecular substances. This study aims at evaluation of kinetics of lignocellulosic biomass of leaves and stems of Hibiscus rosa sinensis and Nerium oleander under pyrolytic conditions, their proximate and ultimate analyses and their calorific values. Pyrolysis experiments were carried out using a thermogravimetric balance, which combines heat flux type differential thermal analysis (DTA) with thermogravimetric analysis (TGA) at different heating rates under a nitrogen atmosphere. The results were analyzed using weight loss vs. temperature and derivative weight vs. temperature profiles obtained from DTA and TGA curves. Three kinetic stages apart from moisture evaporation were observed based on the type of biomass. Kinetic parameters such as the pre-exponential factor and activation energy for each degradation step were calculated using first-order kinetics. The assumption of first-order kinetics was also proved from the experimental data. The results showed that Nerium oleander leaves are more suitable for fuel production through pyrolysis due to their higher percentage of volatile matter, low sulfur content, lower ash content, higher calorific value and lower activation energy required to decompose constituents of biomass, namely hemicellulose, cellulose and lignin.

СИНТЕЗ ТА ДОСЛІДЖЕННЯ ТЕРМОСТАБІЛІЗУЮЧОЇ ДІЇ НА ПОЛІСТИРОЛ МЕТАКРИЛОВИХ МОНОМЕРІВ НА ОСНОВІ АУРОНУ

In this work, 6-hydroxy- and 4'-hydroxyaurones were synthesized by condensation reaction of 6-hydroxybenzofuran-3-one with benzaldehyde and benzofuran-3-one with 4-hydroxybenzaldehyde. Methacrylic monomers – (2Z)-6-methacryloxy-2-(4-R-benzylidene)-1-benzofuran-3-(2H)-one and a new 4-[(Z)-(3-oxo-1-benzofuran-2-(3H)ilidene)methyl]phenyl-2-methyl acrylate were obtained by acylation with the methacryloyl chloride in the presence of triethylamine as HCl acceptor at the temperature 0–5°C. These monomers were synthesized to create special purpose polymers. New methacrylic derivatives are not deeply painted and stable in air crystalline monomers. The structure of the synthesized compounds was confirmed by spectral methods. 1H NMR (400 MHz) spectra were recorded on a Mercury (Varian) 400 spectrometer with tetramethylsilane as internal standard in DMSO-d6. The intrachain thermostabilizing effect of these monomers on the polystyrene destruction processes was studied. Polystyrene and its modified samples were obtained by radical thermoinitiated polymerization (initiator – azo-bis-isobutyronitrile – 1 mass percent) in ethyl acetate at the temperature 78°C during 16 hours. In a case modified samples, 3 mol percent of aurone containing monomers were added. Destruction of modified polystyrene was studied by using dynamic thermogravimetric analysis. Destruction of modified polystyrene was carried out in a Simultaneous Differential Thermogravimetric Analyzer which combines a heat-flux type DTA with a TGA (Shimadzu, DTG-60, Japan). Simultaneous TG, DTG and DTA curves were obtained and sample weight loss as functions of time and temperature were recorded continuously under dynamic conditions. Sintered a-alumina was used as the reference material. Sample with mass of 4 mg was inserted directly into platin crucible and temperature was ramped from 20 to 600°C. The heating rates were controlled at 10°C/min. Experiments were performed under an air atmosphere. It was established, that the investigated additives covalently attached to the polystyrene are inhibited the polystyrene destruction processes. Moreover, the additive with the methacrylic group in 6-position of the aurone is significantly more efficient than with the methacrylic group in 4’- position. It has been shown that samples of modified polystyrene by the applications of 4'-methacryloxy aurone and 6-methacryloxy aurone are more thermostable than the industrial sample of polystyrene of brand STYRON (Switzerland). It was shown that the temperature of 10% of the mass loss of modified samples is higher on 14–34 degrees than for the sample of polystyrene of brand STYRON. Thus, the new additives could be proposed for thermostabilizing of polystyrene production.