Non-uniform Heat Research Articles

Thermodynamics of hydromagnetic boundary layer flow of Prandtl nanofluid past a heated stretching cylindrical surface with interface slip

BackgroundThe mathematical modelling of a non-Newtonian fluid in the backdrop of applied magnetic field against an electrically conducting liquid is recognized as magnetohydrodynamics (MHD), which has important implications in chemical engineering and the biological sciences. Illustrations of such magneto-fluids include molten metals, electrolytes, blood plasma, and salty water. The applications of flowing liquids over cylindrical geometries is a fascinating due to its wide range importance in engineering. The aforementioned uses of MHD encourage scientists and analysts to establish new mathematical modelling in the area of fluid dynamics. Therefore, we considered the Prandtl fluid flow with loaded nanoparticles over a cylindrical tube with slip triggered by wall shear stress. The transport equation involving thermophoresis and Brownian diffusions are modelled using the Buongiorno model. The modelling of energy and entropy are established considering the effects of frictional dissipation, non-uniform heat source, thermal stratification, and Ohmic heating. MethodsThe formulated mathematical model leading to a complex system of partial differential equations with numerous integrated parameters. Using numerical algorithm RK-45 with a tolerance limit of 10−6, the system of resultant ordinary differential equations is simulated. The solver is used repeatedly to select the parameters that best meet the intended boundary conditions. Significant findingThe results of the current study revealed that the influence of heat source and thermal stratification on fluid temperature are conflicting. Additionally, the magnetic variable and Brinkman parameter have an escalating relationship with the rate of entropy development. The Bejan number detract with the magnetic variable. For distinct estimations of slip factors, heat and mass transport behave identically. However, the effect of slip is higher as compared to no slip scenario. The effect of Lewis number against nanoparticles concentration is opposite.

Unveiling impacts of heat flux distribution on forced convection in horizontal evacuated tubes

Integration of evacuated tubes with solar thermal desalination can significantly enhance thermal efficiency and water production. To provide optimization strategies for such desalination systems, 3D numerical simulations were performed to analyze the influence of the heat flux distribution on forced convection in horizontal evacuated tubes in terms of pressure drop, secondary flow, temperature distribution, and Nu. The improved method considered multi-layer wall heat transfer, fluid–solid coupling heat transfer, and temperature dependent fluid properties. Non-uniform heat fluxes significantly affected the friction pressure drop in the laminar regime, but were less pronounced in the transition and turbulent regimes. At low Re, the backward non-uniform heat flux strengthened the secondary flow while the forward non-uniform heat flux suppressed it. The rapid warming of the wall temperature occurred over a short distance due to the difference in thermal conductivity between the fluid and solid domains. The non-uniformity of heat flux distribution moderately affected average fluid temperature. The influence of heat flux distribution on secondary flow and average temperature weakened as Re increased. Furthermore, a correction factor was introduced to quantify the impact of heat flux distribution on Nu. For forward and backward non-uniform heat fluxes, it assumes values of 0.94 and 0.86 respectively.

Numerical analysis of Marangoni convected dusty second-grade nanofluid flow in a suspension of chemically reactive microorganisms

The present work investigates the Magneto-Marangoni convective flow of dusty second-grade nanofluid flow over a porous sheet in the presence of stagnation-point. The effects of chemical reaction, gyrotactic microorganisms are taken into account along with variable mass diffusivity, thermal radiation, and non-uniform heat source. The thermal reflection of nanoparticle molybdenum disulfide ([Formula: see text]) when it interacts with kerosene oil (KO) base fluid is determined. Nanoparticles and dust particles are presumptively spherical. The arising system of nonlinear PDEs is transformed into nonlinear ODEs by applying similarity transformations. Conservation of momentum, mass, concentration, energy, and density of microorganisms are used in to model the flow equations. The numeric expressions are computed by using the RKF-45th based shooting scheme. The outcomes revealed that the microorganisms, concentration, and temperature profiles decay in both phases, but velocity profiles of dust and fluid phases rise as the Marangoni ratio parameter grows.

Analysis and testing of tread braked railway wheel — Effects of hot spots on wheel performance

To investigate the impact of localised heating phenomena in the form of hot spots on wheel performance in general and on wheel residual stress state in particular, a combination of experimental testing and finite element simulations of tread braked wheels has been performed. Using a newly established full-scale railway brake test rig, a wheel is exposed to prolonged drag braking applications at constant power levels to induce high temperatures on the wheel tread. The distribution and evolution of the temperature is studied using a high-speed, high-resolution thermographic camera in addition to traditional sliding thermocouples. Measured temperature data are then used in combination with a thermomechanically calibrated material model to simulate the wheel behaviour. For this purpose, a 3D finite element model representing a sector of a railway wheel is used. The experimental results show that the temperatures measured utilising sliding thermocouples provide insufficient information since they cannot resolve the uneven tread temperatures given typical response times. Non-uniform heating is found to have a significant effect on tensile residual stresses in the rim. Especially the case with global uneven temperatures is found to generate potentially hazardous residual stresses. The results presents future challenges for the analysis and development of the brake-wheel-rail system.

Numerical treatment of the radiated and dissipative power-law nanofluid flow past a nonlinear stretched sheet with non-uniform heat generation

The main aim of this paper is to investigate the effect of non-uniform heat generation and viscous dissipation on the boundary layer flow of a power-law nanofluid over a nonlinear stretching sheet. Within the thermal domain, the analysis considers both thermal radiation and variable thermal conductivity. Through the use of similarity transformations, the governing boundary layer equations are transformed into a system of ODEs. The spectral collocation method (SCM) with shifted Vieta-Lucas polynomials (VLPs) is implemented to give an approximate expression for the derivatives and then use it to numerically solve the proposed system of equations. By employing this technique, the system of ODEs is converted into a system of nonlinear algebraic equations. The dimensionless temperature, concentration, and velocity are graphically presented and analyzed for various values of the relevant governing parameters. Through the presented graphical solutions, we can see that the main outcomes indicate that an increase in the power law index, thermal conductivity parameter, and radiation parameter leads to a noticeable decrease in the local Nusselt number, with reductions of around 0.05 percent, 0.23 percent, and 0.11 percent, respectively. In contrast, the Prandtl parameter demonstrates an opposing effect, elevating the local Nusselt number by about 0.1 percent. We validated the accuracy of the numerical solutions by comparing them in some special cases with existing literature.

Mathematical modelling of entropy generation in radiative non-Darcy flow of a Carreau-Yasuda nanofluid in a rotating channel with activation energy, Hall current and the Cattaneo-Christov heat flux

The current research investigates entropy generation in magnetohydrodynamic rotating multiple slip flow of Carreau-Yasuda nanofluid between parallel plates within a non-Darcy porous medium, considering factors such as viscous dissipation, Joule heating, Hall current, and nonuniform heat generation. The Carreau-Yasuda model, applicable to non-Newtonian fluids like blood and shampoo, is employed to comprehend rheological behavior. This study holds significance in industrial, technological, and medical domains, impacting areas like drilling muds, metallurgy, and cardiac MRI. Nonlinear thermal radiation enhances model realism. The research delves into chemical reactions influenced by activation energy. The mathematical model is formed using nonlinear partial differential equations with multiple slip boundary conditions, and addressed using a compatibility-based similarity transformation. Numerical solutions employ the successive linearization coupled with Chebyshev spectral collocation method. MATLAB-generated graphs and tables illustrate the influence of flow parameters on the physical quantities. The investigation reveals inverse and favoring trends of the Weissenberg number to the energy field in shear-thinning and shear-thickening scenarios, respectively. Velocity slip is found to diminishes entropy production in the channel.

Pressure Drop Characteristics of Subcooled Water in a Hypervapotron under High and Non-Uniform Heat Fluxes

To study the pressure drop characteristics of hypervapotron, which was designed as a water-cooling structure in the divertor dome of the fusion reactor, the pressure drop tests of subcooled water were carried out in a vertically upward hypervapotron. To simulate the one-side radiant heating condition in the engineering application, the non-uniform heat fluxes were obtained by using the off-center electrically heating method. The system parameters were as follows: mass flux G = 2000–5000 kg·m−2·s−1, inlet pressure p = 2–4 MPa, and equivalent one-side radiating heat flux qe = 0–5 MW·m−2. The effects of the parameters on the pressure drop were discussed in detail. It was observed that in the single-phase (SP) region, the pressure drop was little influenced by the inlet fluid temperature (Tb,in). However, in the subcooled boiling region, the pressure drop increased rapidly with the increasing Tb,in. A higher G leads to a high pressure drop. In the SP region, the influence of p on the pressure drop is not obvious, and the pressure drop decreased with the increasing qe. The test data are used to evaluate the typical pressure drop correlation, and the results show that none of these correlations can predict the pressure drop well under the test conditions. Therefore, a new pressure drop correlation is proposed for subcooled water in a hypervapotron under high and non-uniform heat fluxes. The new correlation has a high prediction accuracy for the test data, and the mean relative error (MRE) and root mean square error (RMSE) are 0.72% and 4.33%, respectively. The test results have a reference value for the design of the water-cooling structure of the diverter.

Terahertz bow-tie diode based on asymmetrically shaped AlGaN/GaN heterostructures

Asymmetrical shaping of AlGaN/GaN heterostructures containing a conductive layer of two-dimensional electron gas (2DEG) was used for the development of bow-tie (BT) diodes for room temperature terahertz (THz) detection. Considering operation of the THz BT diode in the unbiased mode as preferable for practical applications, we investigated the diodes with an obvious asymmetry of IV characteristics, which was found to be more pronounced with the decrease of an apex width, resulting in the sensitive THz detection. A nonuniform heating of carriers in a metalized leaf of the BT diode was attributed as the main mechanism that caused the rectification of THz waves. The responsivity and noise-equivalent power (NEP) at the fundamental antenna frequency of 150 GHz were up to 4 V/W and 2 nW/√Hz, respectively. Such high sensitivity of BT diodes allowed us to measure for the first time the response spectrum of the asymmetric BT antenna demonstrating fundamental and higher order resonances in good agreement with finite-difference time-domain simulation data in a broad spectrum range. The detailed investigation of the lowand high-frequency noise characteristics of AlGaN/GaN BT diodes revealed that only thermal noise needs to be considered for the unbiased operation, the value of which was relatively low due to a high density of 2DEG enabling low resistivity values. Moreover, we observed that the responsivity of BT diode scales with its resistance, revealing that tapering of the diode apex below a few microns could be ineffective in applications which require low NEP values.

Effect of non-uniform heat rise/fall and porosity on MHD Williamson hybrid nanofluid flow over incessantly moving thin needle

In this work, a novel enhanced model of the thermophysical characteristics of hybrid nanofluid is introduced. An innovative kind of fluid called hybrid nanofluid has been engineered to increase the heat transfer rate of heat and performance of thermal system. A growing trend in scientific and industrial applications pushed researchers to establish mathematical models for non-Newtonian fluids. A parametric study on theheat transfer and fluid flow of a Williamson hybrid nanofluid based on AA7075-AA7072/Methanol overincessantly moving thin needle under the porosity, Lorentz force, and non-uniform heat rise/fallis performed. Due to similarity variables, the partial differential equations governing the studied configuration undergo appropriate transformation to be converted into ordinary differential equations. The rigorous built-in numerical solver in bvp4c MATLAB has been employed to determine the numerical solutions of the established non-linear ordinary differential equations. It is worthy to note that velocity declines for both AA7075/Methanol nanofluid and AA7075- AA7072/Methanol hybrid nanofluid, but highervelocitymagnitudes occur for theAA7075/Methanol whilethe Williamson fluid parameters increased. It is alsoconcluded that as the porosity parameter isincreased, the flow intensity decreases gradually. It is worthy to note that for both non-uniform heat-rise and fall parameters, the temperature of the fluid gets stronger. Mounting valuesof needle thickness parameter leads to reduction in fluid speed and temperature. It is noticedthat as volume fractions of both types of nanoparticles are augmented then fluidvelocity and temperature amplify rapidly. A Comparison of current and published results is performed to ensure the validity of the established numerical model.

Application of acoustic vibration promotes heat transfer of high-viscosity fluid in a container

The inferior fluidity of high-viscosity liquids hinders their efficacy in heat transfer, resulting in non-uniform heat distribution and occasional overheating, which significantly impairs process and product quality. In this study, we aim to investigate the effect of acoustic vibrations on heat transfer in sealed containers containing high-viscosity fluids by employing computational fluid dynamics (CFD). We established a VOF model and validated it through experiments. Through the collaborative analysis of the velocity field and temperature field, the mechanism of vibration-enhanced heat transfer was revealed. The results of the study indicate that acoustic vibration can enhance convective flow and improve field synergy between the temperature and velocity fields, leading to improved temperature uniformity and heat transfer efficiency. Heat transfer efficiency shows a positive correlation with vibration frequency and amplitude, though no significant correspondence is found with vibration acceleration. Within a certain range, the heat transfer efficiency is more sensitive to the changes in low amplitude or the changes in high frequency. Within a certain range of acceleration, large amplitude with low frequency has a better effect on heat transfer. Finally, we developed a functional relationship between heat transfer efficiency and vibration parameters to predict the heat transfer effect under different parameters, providing suggestions for specific process optimization.

Comprehensive analysis method of acquiring wall heat fluxes in rotating detonation combustors

Accurate perception of the combustor thermal environment is crucial for thermal protection design of a rotating detonation combustor (RDC). In this study, a comprehensive analysis method is established to calculate the non-uniform heat flux distribution of the RDC by utilizing the measured temperature distribution of the combustor outer wall obtained by the high-speed infrared thermal imager. Firstly, a physical model based on the geometric characteristics of the RDC is constructed and its thermal conductive process is simulated, given by different heat flux boundary conditions. The analysis results indicate that the method used in current research for computing the heat flux of RDC leads to significant discrepancies, particularly in regions of obvious axial heat flux gradients near the top of the combustor. Then the Levenberg-Marquardt (L-M) method for inversely solving non-uniform heat flux is developed based on the two-dimensional heat conduction equation, and the wall heat fluxes are inversely calculated by the L-M method based on the above numerical data. Results show that the L-M method can obtain more accurate heat flux distribution even in the zones with large heat flux gradients, considering the axial heat conduction within the combustor outer wall caused by the non-uniform heat flux. Finally, the wall heat flux distribution is analyzed coupling the L-M method together with the experimental measurements in kerosene two-phase RDC. The analyses show that the wall heat flux exhibits non-uniform distributions both circumferentially and axially, with axial non-uniformity being particularly pronounced. The highest temperature of combustor outer surface and the highest wall heat flux occurs within the region of 20 mm from the combustor head, which corresponds to nearly 14 % of the combustor length. The heat flux peak and thermal heat rate are positively correlated with the combustor equivalence ratio in the range between 0.44 and 0.64. In this study, the distribution of wall temperature field in the two-phase RDC is obtained for the first time and the wall heat flux is calculated inversely by L-M method. This work provides a more accurate method for calculating heat flux in RDC and offers references for thermal protection designs in RDCs.

Unsteady Boundary Layer Heat and Mass Transfer Flow of Nanofluid Over Porous Stretching Sheet with Non-Uniform Heat Generation/Absorption and Double Stratification

The influence of thermal radiation and stratification process on unsteady MHD flow over stretching sheet embedded in “nanofluid saturated porous medium with non-uniform heat source/sink was analyzed numerically in the present analysis. Proper similarity transformations reduce the nonlinear partial differential equations into ordinary differential equations and are solved numerically by using Galerkin Finite element method. Impact of different parameters, such as, magnetic parameter (0.1–1.0), buoyancy ratio parameter (0.1–4.5), radiation parameter (0.5–1.7), Rayleigh number (0.1–0.7), thermophoresis parameter (0.4–1.5), thermal stratification parameter (0.01–1.0), Brownian motion parameter (1.0–2.0), solutal stratification parameter (0.01–1.0), unsteadiness parameter (0.1–0.4), space–dependent (-0.5–0.4) and temperature dependent (-0.5–0.2) heat source/sink parameters on velocity, temperature and concentration profiles is calculated and are illustrated graphically. Skin-friction coefficient, Nusselt and Sherwood number are calculated and the results are shown in tabular form. It is found that the thermal stratification parameter deteriorates the temperature of the fluid. The concentration of the fluid diminishes with rising values of solutal stratification parameter. The thermal boundary layer thickness elevates” with higher values of Brownian motion and thermophoresis parameters.

The influence of a self-focused laser beam on the stimulated Raman scattering process in collisional plasma

The influence of a self-focused beam on the stimulated Raman scattering (SRS) process in collisional plasma is explored. Here, collisional nonlinearity arises as a result of non-uniform heating, thereby causing carrier redistribution. The plasma density profile gets modified in a perpendicular direction to the main beam axis. This modified plasma density profile greatly affects the pump wave, electron plasma wave (EPW) and back-scattered wave. The well-known paraxial theory and Wentzel–Kramers–Brillouin approximation are used to derive second-order ordinary differential equations for the beam waists of the pump wave, EPW and the scattered wave. Further to this, the well-known fourth-order Runge–Kutta method is used to carry out numerical simulations of these equations. SRS back-reflectivity is found to increase due to the focusing of several waves involved in the process.

Thermal buckling behavior of 3D printed foams: Plain, graded, and sandwich variants

The present work focuses on the experimental investigation of the thermal buckling response of 3D printed functionally graded glass micro balloon (GMB) reinforced high density polyethylene (HDPE) composites and their respective sandwiches under non-uniform heating conditions. The influences of GMB loading and its graded composition on temperature distribution are analyzed. The reinforcement of hollow GMB rendered lower thermal conductivity due to enhanced thermal resistance with an increase in filler percentage. An increased thermal buckling strength is also observed. Due to their non-uniform thermal expansion, functionally graded sandwich beams exhibited less deflection than plain beams. Among the cases of three heating conditions (One end heating: case-1, Center heating: case-2, both end heating: case-3), maximum deflection is observed in case 2 while the minimum deflection is noted in case 1. These printed foams can be utilized for lightweight thermal insulating pipes.

Heating performance of dual-source microwave heating using different frequency shifting strategies in a solid-state system

Solid-state microwave heating holds potential in mitigating the issue of nonuniform heating commonly observed in magnetron-based microwave ovens. Previous work on solid-state application primarily focused on single-source microwave heating and modeling of dual-source heating with fixed frequency combinations. This study experimentally investigated the port interactions and heating performance of four different frequency shifting approaches (in range of 2.4 and 2.5 GHz, at an interval of 0.01 GHz), i.e., Fixed-frequency without shifting, Synchronized-shifting, Inverse-shifting and Distinct-shifting, in a dual-source microwave system under both stationary and rotatory conditions. Results showed that port interactions were dependent on the microwave frequency and load position, both of which significantly affected the microwave power efficiency. All three shifting strategies significantly improved heating performance compared to the Fixed-frequency heating. Additionally, the use of a turntable in our dual-source microwave configuration did not improve the heating uniformity in the context of various frequency shifting processes, suggesting that the inclusion of a turntable might be dispensable in solid-state microwave systems if proper multi-port frequency shifting strategy could deliver more uniform heating.

Effect of cavity radiation on aluminium hollow tubes and facade system subjected to fire

PurposeThis paper numerically investigates the effect of cavity radiation on the thermal response of hollow aluminium tubes and facade systems subjected to fire.Design/methodology/approachFinite element simulations were performed using ABAQUS 6.14. The accuracy of the numerical model was established through experimental and numerical results available in the literature. The proposed numerical model was utilised to study the effect of cavity radiation on the thermal response of aluminium hollow tubes and facade system. Different scenarios were considered to assess the applicability of the commonly used lumped capacitance heat transfer model.FindingsThe effects of cavity radiation were found to be significant for non-uniform fire exposure conditions. The maximum temperature of a hollow aluminium tube with 1-sided fire exposure was found to be 86% greater when cavity radiation was considered. Further, the time to attain critical temperature under non-uniform fire exposure, as calculated from the conventional lumped heat capacity heat transfer model, was non-conservative when compared to that predicted by the proposed simulation approach considering cavity radiation. A metal temperature of 550 °C was attained about 18 min earlier than what was calculated by the lumped heat capacitance model.Research limitations/implicationsThe present study will serve as a basis for the study of the effects of cavity radiation on the thermo-mechanical response of aluminium hollow tubes and facade systems. Such thermo-mechanical analyses will enable the study of the effects of cavity radiation on the failure mechanisms of facade systems.Practical implicationsCavity radiation was found to significantly affect the thermal response of hollow aluminium tubes and façade systems. In design processes, it is essential to consider the potential consequences of non-uniform heating situations, as they can have a significant impact on the temperature of structures. It was also shown that the use of lumped heat capacity heat transfer model in cases of non-uniform fire exposure is unsuitable for the thermal analysis of such systems.Originality/valueThis is the first detailed investigation of the effects of cavity radiation on the thermal response of aluminium tubes and façade systems for different fire exposure conditions.

Sensitivity analysis on enhanced thermal transport in Eyring–Powell nanofluid flow: investigating over a radiating convective Riga plate with non-uniform heat source/sink under flux conditions

Sensitivity analysis on enhanced thermal transport in Eyring–Powell nanofluid flow: investigating over a radiating convective Riga plate with non-uniform heat source/sink under flux conditions

Improving the Heat Transfer Performance of the Tower Molten Salt Solar Receiver With the Novel Folded Flow Tubes

Abstract The molten salt has been widely used in concentrated solar power generation as an effective high-temperature heat transfer and heat storage working fluid. However, due to the concentrating characteristic of the tower receiver, the solar flux distribution of the molten salt receiver is extremely non-uniform, and thus the circumferential non-uniform heat flux has a prominent effect on the heat transfer performance and reliability of the traditional solar molten salt receiver tube (TRT). In this contribution, in order to solve above problems, we propose some novel folded flow tubes (NFTs), which add a partition in the tube and seal the top with end cap so that the inflow and outflow of the fluid can only proceed from the same cross section. Then, we apply the binary nitrate (solar salt) as a heat transfer fluid, which is a mixture of 60% sodium nitrate and 40% potassium nitrate. First, we analyze some effects such as flow parameters, structure, and heat flux loading direction on the convective heat transfer performance of the NFTs. The results show that the circumferential temperature difference of NFTs is about 17–92 K lower than that of TRT, and the molten salt temperature distribution is more uniform accordingly. Moreover, the heat transfer coefficient is increased about 88.37–122.85%, which can provide a guidance for the structural optimization of practical solar molten salt receivers to improve the heat transfer performance and reliability.

Modelling heat-mass transport for MHD Eyring-Powell hybrid nanofluid over an expanding surface laden by autocatalytic chemical reaction and nanoparticles diffusion

Prior hybrid nanofluid research is restricted to single or two-phase models, which were dominated by homogeneous nanofluid models. These models adhere a serious flaw with the heat-mass transfer indices. To handle this problem, we develop an entirely novel hybrid nanofluid models based on the fundamental slip mechanisms of nanofluids induced by Brownian and thermophoretic diffusion as well as the chemical reaction of binary species. The laminar flow of MHD rheological model with suspended nanoparticles is striking at the stagnation region laden over a stretching surface. In order to reach the real world scenario, the expression of radiative heat, non-uniform heat source and frictional heating are all included. The coupled Buongiorno's model and Tiwari-Das mixtures models incorporate the effect of particles diffusion and volumetric friction, respectively. It is hypothesized that first order kinetics can describe homogeneous events in the immediate proximity, while isothermal cubic autocatalysis kinetics frequently describe heterogeneous reactions occur on the sheet surface. The restructured mathematical equations are solved with a proficient Runge Kutta Fehlberg technique together with the shooting procedure. According to the outcomes, the presence of higher magnetic field diminished the flow and velocity gradient. The effect of elastic parameters is diminishing frictional coefficient. The effect of first and second Brownian (Nb1, Nb2) and thermophoretic parameters (Nt1, Nt2) are similar for temperature. The mass-heat transfer rate is significant with higher estimations of diffusivity ratio Nbt. The momentum rate of diffusion outweighs the species diffusion rate as the Schmidt number increases, resulting in a decrease in concentration values. Higher intensities of Lorentz's force results in denser streamlines. The streamlines split into an opposite direction because of stagnation point.

Double-diffusive convection in a porous layer subjected to an inclined temperature gradient incorporating Soret effect

In several commonly occurring natural convection phenomena, the system is subjected to non-uniform heating that causes an inclined thermal gradient. As a result, the natural convection problem deviates from the classical Rayleigh–Bénard problem, in which the thermal gradient has only a vertical component. In this study, we present linear and global stability analyses results concerning thermosolutal convection in a Newtonian fluid-saturated Darcy porous layer subjected to an inclined thermal gradient in the presence of the Soret effect (associated with thermophoresis). The thermal gradient is assumed to have horizontal and vertical components, resulting in the formulation having two thermal Rayleigh numbers as system parameters, viz. horizontal and vertical Rayleigh numbers. The horizontal thermal gradient gives rise to a Hadley-type circulation. This circulation can become unstable if the vertical thermal gradient attains a certain threshold. We focus on the effect of the Soret parameter on the system’s stability under non-uniform inclined heating. The analyses reveal that the solutal Darcy–Rayleigh number and Lewis number destabilise the system, while the Soret parameter has a non-monotonic effect on the system’s stability depending on the horizontal Rayleigh number. The energy stability bounds do not coincide with linear ones for the present problem; hence, subcritical instabilities are possible.