Buoyancy Component Research Articles

Study on the flame radiative heat transfer and near-field radiation heat flux predictive model of vehicle fires in a tunnel

As a major form of heat transfer, flame thermal radiation has an important effect on the ignition of adjacent energy, fire spread and environmental damage. Forecasting the flame radiation heat flux can provide theoretical basis for fire hazard assessment, fire extinguishing and salvation. Meanwhile, the distinctive structure of the arc tunnel can result in significant variations in the local heat and mass transfer processes during tunnel fires compared to those in rectangular tunnels, leading to different fire characteristics parameters. In this study, experiments and theoretical analyses were conducted to investigate the flame length scale and near-field radiation heat flux on the lower surface of an arc-shaped ceiling induced by vehicle fires in a tunnel. The findings reveal that the flame length scale in the transverse direction beneath the arc-shaped ceiling decreases with an increasing burner aspect ratio and increases with the increasing heat release rate. A dimensionless model of the flame length scale under the arced ceiling with various burner aspect ratios was proposed based on the amount of remaining unburned fuel after flame impingement and the buoyancy component along the arc-shaped ceiling. Simultaneously, radiative heat fluxes on the lower surface also increase with rising heat release rate. The flame geometry beneath the arc-shaped ceiling is assumed to be a combination of a cuboid and an arc plate model based on the actual flame length scale. Subsequently, the view factor, radiative fraction, and flame surface area are analyzed to predict the radiative heat fluxes on the lower surface. The predictions of the cuboid and arc plate flame model show good agreement with the current experimental data. This work presents a dimensionless correlation of the flame length scale and calculates the view factor between the target and the arc plate to predict the near-field radiative heat flux more accurately. This approach also facilitates the understanding of flame spreading behavior and thermal hazards impacted by arced ceiling.

Experimental study on the morphology of turbulent diffusion flames with different aspect ratios under slope conditions

In this paper, the morphology of turbulent diffusion flames with varying aspect ratios under slope conditions was investigated. A simulated fire source using propane gas with an area of 80 cm2 was utilized. The influences of slope angle and aspect ratio of the fire source on the flame tilt angle (between the plume centerline and the slope), flame length, and flame height were systematically studied. The aspect ratio of the fire source (L/W) was changed from 1 to 8, and the slope angle was changed from 0° to 40°. Results indicate that the presence of a slope causes asymmetrical air entrainment on both sides of the fire plume, causing a pressure difference that leads to a decrease in the flame tilt angle as the slope angle increases. Additionally, the flame length increases monotonically with the slope angle due to the enhanced component of thermal buoyancy along the slope. Under the same slope condition, the flame tilt angle and flame height (perpendicular to the slope) decrease as the aspect ratio increases. This phenomenon is attributed to the increased entrainment restriction effect of the slope on the fire plume. New models for calculating flame tilt angle, flame length, and flame height, which consider the slope angle and aspect ratio of the fire source were established by using the equivalent perimeter of plume entrainment. To further verify the reliability of the newly established models, reference data with wide heat release rate (6.15 kW–231 kW), different slope inclination angle (0°–80°), pool size (equivalent diameter: 9 cm–44.1 cm), and different fuels (propane, ethylene) were used to against with the predicted values of our correlations. It is found that the maximum error of all correlations is within 15–20%, their universality and accuracy are further verified.

Magnetic dipole effects on unsteady flow of Casson-Williamson nanofluid propelled by stretching slippery curved melting sheet with buoyancy force

In particular, the Cattaneo-Christov heat flux model and buoyancy effect have been taken into account in the numerical simulation of time-based unsteady flow of Casson-Williamson nanofluid carried over a magnetic dipole enabled curved stretching sheet with thermal radiation, Joule heating, an exponential heat source, homo-heterogenic reactions, slip, and melting heat peripheral conditions. The specified flow's partial differential equations are converted to straightforward ordinary differential equations using similarity transformations. The Runge–Kutta–Fehlberg 4-5th order tool has been used to generate solution graphs for the problem under consideration. Other parameters are simultaneously set to their default settings while displaying the solution graphs for all flow defining profiles with the specific parameters. Each produced graph has been the subject of an extensive debate. Here, the analysis shows that the thermal buoyancy component boosts the velocity regime. The investigation also revealed that the melting parameter and radiation parameter had counterintuitive effects on the thermal profile. The velocity distribution of nanofluid flow is also slowed down by the ferrohydrodynamic interaction parameter. The surface drag has decreased as the unsteadiness parameter has increased, while the rate of heat transfer has increased. To further demonstrate the flow and heat distribution, graphical representations of streamlines and isotherms have been offered.

Inclination‐Enabled Generalized Microfluid Rectifiers via Anisotropic Slippery Hollow Tracks

The power of spontaneous maneuvering of microfluids that allow gas or liquid to penetrate along a single direction, is usually endowed with the wettability gradient and the Laplace pressure difference through tailoring special solid‒gas interfacial geographies. Herein, inspired by the structures on rice leaves and the slippery surfaces of the pitcher plant, anisotropic slippery hollow tracks (ASHTs) are fabricated and thus propose a class of unique inclination‐enabled bubble “diode”, on which one‐way bubble penetration can be reversibly switched on/off. The minimum transition tilt angle is subject to the tract spacing and the infused oil amount. The underlying mechanism of bubble penetration is attributed to the competition between the variable buoyancy component and the interfacial energy gradient perpendicular to the samples. A wide spectrum of generalized microfluid maneuvering capabilities is further demonstrated, including heavy oil selective penetration, underwater CO2 gas collection, and even dry/wet environment management in smart buildings, which are challenging for conventional counterparts. This framework should facilitate the development of microfluid control with favorable retainability and wide applicability in multiple fluids.

Nonlinear Mixed Convection in a Reactive Third-Grade Fluid Flow with Convective Wall Cooling and Variable Properties

Energy management and heat control whenever a reactive viscous fluid is the working medium has been one of the greatest challenges encountered by many in the field of chemical and industrial engineering. A mathematical approach to thedetermination of critical points beyond which the working environment becomes hazardous is presented in the present investigation together with the entropy generation analysis that guarantees the efficient management of expensive energy resources. In this regard, the nonlinear mixed convective flow behavior of a combustible third-grade fluid through a vertical channel with wall cooling by convection is investigated. The mathematical formulation captures the nonlinearities arising from second-order Boussinesq approximation and exponential dependence of internal heat generation, viscosity, and thermal conductivity on temperature. The resulting nonlinear boundary value problems were solved based on the spectral Chebyshev collocation method (SCCM) and validated with the shooting-Runge–Kutta method (RK4). The nonlinear effects on the flow velocity, temperature distribution, entropy generation, and Bejan heat irreversibility ratio are significant. Further analyses include the thermal stability of the fluid. Findings from the study revealed that flow, temperature, and entropy generation are enhanced byincreasing values of the Grashof number, the quadratic component of buoyancy, and the Frank-Kameneskii parameter, but are reducedbyincreasing the third-grade material parameter. Moreover, it was shown that increasing values of the third-grade parameter encourages the thermal stability of the flow, while increasing values of the linear and nonlinear buoyancy parameter destabilizes the flow. The present result is applicable to thick combustible polymers with increased molecular weight.

Dynamics of the Atlantic Marine Intertropical Convergence Zone

AbstractA generalized ω‐equation is used to identify the contributions from different processes that force upward motions in the Atlantic Marine ITCZ (AMI) from a numerical mesoscale simulation of June 2010. This ω‐equation separates the diabatic heating contributions, which lie at the core of the Weak Temperature Gradient (WTG) framework, from the dynamical terms. Three layers of atmosphere are found with different balance. In the Marine Atmospheric Boundary‐Layer (MABL), the upward motions in the AMI are induced by the frontogenesis and buoyancy components, which are regulated by the ageostrophic adjustment due to the presence of thermal‐wind imbalance. The balance of these three processes well captures the variability of the vertical velocity and the associated precipitation, meaning that boundary‐layer processes play a central role in the AMI dynamics. In the layer [600–2,000 m], a zone of strong vertical wind‐shear just above the MABL, the upward motions are induced by the ageostrophic adjustment and radiative components, which are counteracted by evaporation of convective precipitation. Above 2,000 m the ascending motions are driven by the deep convection heating, as expected by the WTG framework, and more surprisingly by the ageostrophic adjustment term within the Tropical Easterly Jet. Thanks to the use of the ω‐equation, these results extend the current WTG framework to the boundary layer, where it is not expected to hold. In the free troposphere, the WTG framework only accounts for half of the AMI ascent, the other half being forced by the dynamical terms.

Predictions of compression capacity of randomly corroded spherical shells based on artificial neural network

Spherical pressure hull is a key buoyancy component of deep-sea submersibles. Corrosion on the surface of spherical shell can significantly reduce its compression capacity. Pitting corrosion is a typical form of corrosion in steel structures. Artificial neural network (ANN) is utilized to predict the compression capacity of spherical shells with random corrosion and determine influencing factors of corroded spherical shells. Corroded diameter DC/D, corroded thickness TC/T, and mass loss ratio χ are utilized to characterize corrosion severity. The influence of the corroded diameter DC/D and the corroded thickness TC/T on the prediction accuracy is investigated in this study. The applicability of trained ANN for spherical shells with different geometric sizes is validated. Results indicated that ANNs can be utilized for high-precision compressive capacity prediction and the corroded diameter DC/D, corroded thickness TC/T, mass loss ratio χ, and the corroded area can be used as input variables.

Experimental and theoretical analysis on extension flame length of buoyancy-induced fire plume beneath the curved ceiling

The extension flame length is determined by the unburnt fuel mass flow after impingement and the varying buoyancy component along with the curved ceiling. However, the existing model cannot use these two factors to quantitatively describe the extension flame under the curved ceiling. To analyze the extension flame length of the buoyancy-induced fire plume under the curved ceiling, the experimental and theoretical investigation was conducted to analyze the upper extension flame along with the curved ceiling, and the influence of the unburnt fuel mass flow and the varying buoyancy component on the effective heat release rate after impingement was explored in this study. Besides, the prediction equation for the total velocity of the ceiling jet along with the curved ceiling was proposed based on the momentum balance equation. Assuming that there was a linear relationship between the velocity of the ceiling jet and the entrained air, the effective heat release rate was respectively described from the perspectives of the entrained air mass flow and the unburnt fuel mass flow. Based on the above expressions of effective heat release rate after impingement, a new global equation describing the extension flame lengths beneath the curved ceiling was proposed. The validation results show that the proposed equation has a good correlation with the extension flame lengths under the curved ceiling within the relative error range of 15%; therefore, this equation can be effectively applied in the fire protection engineering of the utility tunnel.

Supersaturation, buoyancy, and deep convection dynamics

Abstract. Motivated by recent discussions concerning differences of convective dynamics in polluted and pristine environments, the so-called convective invigoration in particular, this paper provides an analysis of factors affecting convective updraft buoyancy, such as the in-cloud supersaturation, condensate and precipitation loading, and entrainment. We use the deep convective period from simulations of daytime convection development over land discussed in our previous publications. An entraining parcel framework is used in the theoretical analysis. We show that for the specific case considered here, finite (positive) supersaturation noticeably reduces pseudo-adiabatic parcel buoyancy and cumulative convective available potential energy (cCAPE) in the lower troposphere. This comes from keeping a small fraction of the water vapor in a supersaturated state and thus reducing the latent heating. Such a lower-tropospheric impact is comparable to the effects of condensate loading and entrainment in the idealized parcel framework. For the entire tropospheric depth, loading and entrainment have a much more significant impact on the total CAPE. For the cloud model results, we compare ensemble simulations applying either a bulk microphysics scheme with saturation adjustment or a more comprehensive double-moment scheme with supersaturation prediction. We compare deep convective updraft velocities, buoyancies, and supersaturations from all ensembles. In agreement with the parcel analysis, the saturation-adjustment scheme provides noticeably stronger updrafts in the lower troposphere. For the simulations predicting supersaturation, there are small differences between pristine and polluted conditions below the freezing level that are difficult to explain by standard analysis of the in-cloud buoyancy components. By applying the piggybacking technique, we show that the lower-tropospheric buoyancy differences between pristine and polluted simulations come from a combination of temperature (i.e., latent heating) and condensate loading differences that work together to make polluted buoyancies and updraft velocities slightly larger when compared to their pristine analogues. Overall, the effects are rather small and contradict previous claims of a significant invigoration of deep convection in polluted environments.

Analysis of Heat Transfer Oscillation and Buoyancy Effects of Supercritical R1234ze(E) Cooled in Horizontal Helically Coiled Tubes

Abstract The helically coiled tubes (HCTs) have been attracting huge attention for enhancing the heat transfer of supercritical fluids and improving energy efficiency. Moreover, the new refrigerant R1234ze(E) has excellent environmental properties and system performance, but few researches have been concentrated on the supercritical R1234ze(E) heat transfer. In this work, the shear stress transport (SST) turbulence model is adopted for the numerical simulation of the cooling heat transfer performance of s-R1234ze(E) in horizontal HCT. The influences of heat flux, mass flux, coil pitch, and tube radius on the heat transfer coefficient, gravitational buoyancy effect, and centrifugal buoyancy effect are, respectively, investigated. Furthermore, the results reveal heat transfer oscillation occurs when Rig*|cosβ|max>0.17, and the oscillation mechanism is analyzed. Different from that in the vertical HCT, the angle between the radial component of gravitational buoyancy and centrifugal force varies continuously in the horizontal helical tube, resulting in the fluid with lower temperature may locate in the inner-left region or the inner-right region. Subsequently, the heat transfer piecewise correlation for supercritical R1234ze(E) in horizontal HCT is developed. The average absolute deviation of the predicted results is 5.88%.

Шороон шуурга болох үеийн агаар мандлын тогтворшлын параметрүүд

Although many studies investigated the spatial distribution, duration and frequency of dust storm in Mongolia, there are a few studies were undertaken it in terms of physical process that underpinned the current study on the subject. The study examines whether it is possible to acquire the distribution of dust storms in a relatively simple way by estimating the atmospheric stability during a dust storm. In order to achieve the main purpose of the study, the atmospheric stability parameters such as Brunt-Vaisala frequency (N), Gradient Richardson Number (Ri), and Eady Growth Rate (σ_E) were evaluated on 3 different cases of heavy dust storms which are occurred from March to May 2020, covered almost all over Mongolia, using reanalysis data produced by the European Centre for Medium-Range Weather Forecasts and radiosonde data from “Dalanzadgad” an aerological station in Dalanzadgad, Umnugovi. Differential equations of N, Ri, and σ_E are solved using the finite difference method. The results of the study revealed that both Ri and σ_E stability parameters can be identified well the distribution of dust storm, while a linear relationship between a dust storm and N as well as the buoyancy component of Ri was not found. In addition, in the study, a simplified method to compute the Ri parameter based on power function was acquired by the wind shear. It was difficult to make statistical analyses in the results of the study based on few cases between March and May in 2020. Therefore, it is necessary to consider more cases in the future, to undertake statistical analysis.
 
 

Influence of welding parameters on electromagnetic supported degassing of die-casted and wrought aluminum

Laser beam welding of aluminum die casting is challenging. A large quantity of gases (in particular, hydrogen) is absorbed by aluminum during the die-cast manufacturing process and is contained in the base material in solved or bound form. After remelting by the laser, the gases are released and are present in the melt as pores. Many of these metallurgic pores remain in the weld seam as a result of the high solidification velocities. The natural (Archimedean) buoyancy is not sufficient to remove the pores from the weld pool, leading to process instabilities and poor mechanical properties of the weld. Therefore, an electromagnetic (EM) system is used to apply an additional buoyancy component to the pores. The physical mechanism is based on the generation of Lorentz forces, whereby an electromagnetic pressure is introduced into the weld pool. The EM system exploits the difference in electrical conductivity between poorly conducting pores (inclusions) and the comparatively better conducting aluminum melt to increase the resulting buoyancy velocity of the pores. Within the present study, the electromagnetic supported degassing is investigated in dependence on the laser beam power, welding velocity, and electromagnetic flux density. By means of a design of experiments, a systematic variation of these parameters is carried out for partial penetration laser beam welding of 6 mm thick sheets of wrought aluminum alloy AlMg3 and die-cast aluminum alloy AlSi12(Fe), where the wrought alloy serves as a reference. The proportion of pores in the weld seams is determined using x-ray images, computed tomography images, and cross-sectional images. The results prove a significant reduction of the porosity up to 70% for both materials as a function of the magnetic flux density.

Lightweight Liquid Metal Entity

AbstractLiquid metals are of great importance in developing wearable devices and soft robotics owing to its high conductivity and flexibility. However, the high density of such metals turned out to be big concern for many practical situations. With generalized purpose, a new conceptual material as lightweight liquid metal entity, which can be as light as water, is proposed here. For illustration, an unconventionally ultralight material composed of eutectic galliumindium alloys (eGaIn) and glass bubbles is demonstrated, whose density can be reduced below 2.010 even 0.448 g cm‐3, even lighter than water, but still maintains excellent conformability, electric conductivity, and stiffness variety under temperature regulation. Such material is further adopted to build various complicated structures through origami or force regulation, representing various application scenarios and can be reused for eight times without evident loss in function. Based on these tests, buoyancy component for water‐related devices is designed, which offers the functions of a switch and loading element. The lightweight liquid metal entities are promising for making diverse advanced soft robotics and underwater devices in the near future.

Comparison of Local Heat Transfer Distribution in Between Three-Dimensional Inclined Closed and Open Cavities

Abstract The phenomenon of natural convection is investigated in three-dimensional (3D) cavities with four adiabatic walls and one hot wall. The surface opposite to the hot wall is either a wall (closed cavity) at a lower constant temperature or is open to ambient at a lower temperature (open cavity). It is pointed out here that not only overall heat transfer is important, the distribution of local heat transfer is also important. To quantify the uniformity of heat transfer distribution, the ratio of maximum to average heat transfer is calculated for various Rayleigh numbers as well as inclination angles for open and closed cavities. A significant difference in the local heat transfer profile along the hot surface of the closed cavity in comparison to that in open cavity for small inclination angle (especially at higher values of Rayleigh number) is noted. However, the profile is remarkably similar in the case of vertical cavities. For inclined closed cavities, there is a buoyancy component of the flow acceleration normal to the hot and cold wall, which is absent in the case of vertical cavities. For lower inclinations, this component brings the three-dimensionality in the flow field and leads to the differences in the flow patterns. The fluid striking the cold wall in the case of the closed cavity causes significantly different flow patterns that, in turn, lead to nonuniform local heat transfer. To explain the flow behavior, iso-surfaces, stream ribbons, and the Y-components of the flow velocity are plotted at different surfaces of the closed cavity.

Stability of the anabatic Prandtl slope flow in a stably stratified medium

In the Prandtl model for anabatic slope flows, a uniform positive buoyancy flux at the surface drives an upslope flow against a stable background stratification. In the present study, we conduct linear stability analysis of the anabatic slope flow under this model and contrast it against the katabatic case as presented in Xiao & Senocak (J. Fluid Mech., vol. 865, 2019, R2). We show that the buoyancy component normal to the sloped surface is responsible for the emergence of stationary longitudinal rolls, whereas a generalised Kelvin–Helmholtz (KH) type of mechanism consisting of shear instability modulated by buoyancy results in a streamwise-travelling mode. In the anabatic case, for slope angles larger than to the horizontal, the travelling KH mode is dominant whereas, at lower inclination angles, the formation of the stationary vortex instability is favoured. The same dynamics holds qualitatively for the katabatic case, but the mode transition appears at slope angles of approximately . For a fixed slope angle and Prandtl number, we demonstrate through asymptotic analysis of linear growth rates that it is possible to devise a classification scheme that demarcates the stability of Prandtl slope flows into distinct regimes based on the dimensionless stratification perturbation number. We verify the existence of the instability modes with the help of direct numerical simulations, and observe close agreements between simulation results and predictions of linear analysis. For slope angle values in the vicinity of the junction point in the instability map, both longitudinal rolls and travelling waves coexist simultaneously and form complex flow structures.

Temperature profile of impingement flow in the corner between wall and inclined ceiling induced by gaseous fuel jet flame

The present study investigated the temperature profile of impingement flow along the corner between the wall and the inclined ceiling induced by wall-attached gaseous fuel jet flame, which had not been quantified in the literature. Experiments were carried out by using a square nozzle as the burner for various heat release rates, burner-ceiling heights and ceiling inclination angles, with overall 169 experimental conditions considered comprehensively. Results showed that the temperature rise decreased with the increase in inclination angle of the ceiling. It decreased faster along the corner with positive ceiling inclination than that with the negative ceiling inclination. For a negative angle of the ceiling, the inclination angle had more significant effect on the temperature profile with the decreasing of heat release rates and increasing of ceiling heights. While as the inclination angles of the ceiling were positive, it had more significant effect on the temperature profile with the increasing of heat release rates and decreasing of ceiling heights. These behaviors were interpreted based on the analysis on the effects of the rotating vortices of impingement flows in the corner and the buoyancy component along the inclined ceiling. The model proposed by Oka could describe the profile of positive inclination angles well. A new model was developed to correlate the temperature profiles in general for various ceiling inclinations, where the total flame length was found to be the characteristic length scale.

Experimental studies on characteristics of fire whirl in a vertical shaft

SummaryAn internal fire whirl can be generated readily in a tall shaft model with appropriate gap width at one corner. Experimental study was carried out to investigate the relationship between the characteristics of an IFW and the corner gap width in a 9‐m‐tall vertical shaft model. The vertical shaft had a 2.1 m by 2.1 m square section with gasoline pool fire of different diameters burning inside. The gap width was varied to investigate its impact on fire whirl characteristics, such as flame development, swirling intensity, flame height, flame temperature, and heat release rate of the gasoline pool fire. Vigorous flame swirling motions were generated when the ratio of the gap width to the shaft section perimeter was within the range 0.16 to 0.21. From the flame streamline angle, it was observed that the swirling component was much stronger than buoyancy component near the bottom of burning region. The swirling component decreased and became roughly the same as buoyancy near the middle. Finally, it diminished to being much weaker than buoyancy near the top of the fire. These observations suggest that the Froude number Fr decreased from a large number to 1, and then continued to decrease to 0.

Numerical simulation of pool boiling with special heated surfaces

In present work, numerical simulation of the pool boiling at normal environment pressure is performed. Heated surfaces with different geometries, including the plain heated surface and the modified heated surfaces with 36 hemispheres in different orientations, are both investigated. The reliability and accuracy of the present numerical method is verified by comparing the present result with that of the previous experimental one. Then, the relationship between the heat flux (q) and wall superheat (ΔT) is obtained. Moreover, the critical heat flux (CHF) of different surface is obtained as well. It is found that the vessel with modified heated surface has a better heat transfer performance compared to that of plain heated surface. Furthermore, the modified heated surface with downward facing hemispheres has the best heat transfer performance and the lowest critical heat flux (CHF) among the present three heated surfaces, which results from the increasing buoyancy component along the curved surface and the excessive crowded hemispheres at the heated surface, as well as the rough release of vapor bubbles under the condition of higher heat flux.

Simulation and Experimental Studies of a Multi-Tubular Floating Sea Wave Damper

This article explores the issue of shore protection from sea waves and has presented the main methods used for coastal protection. It discusses the construction and operation of the multi-tubular floating sea wave damper that has been developed at the Maritime University of Szczecin by Professor Bolesław Kuźniewski. This paper presents the results of the research project aimed at creating and examining a prototype of the device. The research aimed to confirm the two hypotheses: “the largest damping force should occur when the damping units are placed at an optimal distance equal to half the length of the wave to be damped” and “a compensation of the horizontal forces caused by the rippling of water should occur in the damping device”. Simulation studies of the behaviour of the device’s buoyancy elements when floating on waves were performed using the ANSYS AQWAWB and AQWA software. The buoyancy components were modelled as TUBE elements with a diameter of 0.11 m and a length of 1.5 m and as triangular and square surface elements. The results of the experimental research and the computer simulation of the operation of the prototype device have also been presented. The external conditions adopted corresponded to the frequency of a wave equal to 0.807 Hz and to the wave height in front of the device which was equal to 0.1 m. Experimental studies were conducted in an auxiliary model basin with dimensions of 60 m × 7 m × 3.12 m at the Ship Hydromechanics Division, Ship Design and Research Centre (CTO S. A.) in Gdańsk (Poland). The study recorded the distribution of the vertical and horizontal forces acting on the prototype device as well as the wave height both in front of and behind the device. Both hypotheses were proven. Simulation and experimental studies have been summarised. A proposal for future works has also been presented.

Temperature profile beneath an inclined ceiling induced by plume impingement of gas fuel jet flame

Temperature profile of thermal impingement flow beneath sloped ceiling induced by non-isotropic gaseous fuel jet flame has not been studied before and therefore no data are available in the literatures. Experiments were carried out in this work to measure the temperature distribution in both upward and downward directions beneath the inclined ceiling induced by gaseous fuel jet flame. Different inclination angles, various heat release rates and diverse source-plate heights were considered. Results show that the influence of inclination angle has opposite impacts on the temperature rise for upward flow and downward flow respectively and burner dimension has little effect on the temperature attenuation characteristics while the inclined direction is perpendicular to long side of fire source. The experimental data were compared with correlations predicted by predecessors’ researches and it was observed that the experiment data of upward were consistent with the former correlations while an apparent discrepancy can be found along the downward direction. The influence of buoyancy component force parallel to inclined ceiling was discussed and simply reflected by the cosine value of inclination angle. New relatively uniform correlations were proposed to predict the temperature decay profiles by combing the effects of heat release rates, inclination angles and source-ceiling heights.