Peak Heat Flow Research Articles

Influence of polycarboxylate superplasticizer and calcium sulfoaluminate cement on the rheology, hydration kinetics, and porosity of Portland cement pastes

Binary systems composed of Portland cement (PC) and calcium sulfoaluminate (CSA) cement have stood out for applications requiring high early strengths. Nevertheless, the application of these systems may be limited due to their properties in the fresh state, which requires a better understanding of the rheological behavior of these materials. Thus, this study evaluated the incorporation of different polycarboxylate-based superplasticizer (SP) contents (0.15, 0.20, and 0.25 wt%) on PC and PC-CSA binary cement pastes. Rotational rheometry, isothermal calorimetry, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and nitrogen adsorption and desorption tests to assess the pore size distribution of cement pastes were conducted. While the SP incorporation reduced the dynamic yield stress of PC pastes, it progressively increased the yield stress of PC-CSA systems. The increase in SP content increased the main heat flow peak of PC-CSA pastes, although it did not significantly affect the cumulative heat after 160 h of hydration. FTIR and XRD confirm higher ettringite contents in the binary systems and indicate the presence of carboaluminates phases after 7 d of hydration in both PC and PC-CSA and hemicarboaluminate in PC-CSA pastes. The CSA incorporation reduced the cumulative pore volume by up to 32% compared to PC pastes, while the SP content evaluated did not significantly affect the porosity of PC-CSA pastes.

Reutilization of oil and gas produced water in cement composite manufacturing

Fast-paced urbanism results in the growing demand for more infrastructure, leading to increased concrete production, further depleting freshwater sources. One sustainable solution to diminishing water resources is recycling and reusing non-potable waters and wastewaters in manufacturing operations. This study investigates the reutilization of produced water in cementitious systems. Produced water is the largest volume of waste stream from oil and gas production and usually contains various pollutants such as petroleum hydrocarbons, heavy metals, and toxic chemicals, which may result in unexpected environmental issues. The application of this type of water in a concrete system may not only aid the waste reduction but also yield sustainable concrete and mortar for the construction industry. The current study evaluates the performance of produced water cementitious systems at varying replacement concentration levels. The results indicate that the produced water cementitious system is significantly influenced by water replacement concentration levels. The long-term compressive strength and early age hydration peak heat flow both increase with increasing produced water replacement concentration up to approximately 60% concentration (60% compressive strength increase: 20.2 MPa–32.2 MPa; 120% peak heat flow increase: 2.67 mW/g to 5.92 mW/g). At higher produced water replacement concentrations, the long-term compressive strength and heat of hydration begin to decrease. The produced water leads to increased formation of Friedel's salts and bound calcite, and more polymerization in the calcium silicate hydrate structure. The produced water cementitious systems will increase the long-term compressive strength and early age heat of hydration more than comparable seawater cementitious systems reported in the literature.

Effect of Cellulose Nanofibrils on the Physical Properties and Frost Resistance of Pervious Concrete.

Pervious concrete has good water permeability and, if used in construction, it can alleviate the heat island effect. However, its low strength and poor durability are major obstacles to its use. This study shows that nano-reinforced pervious concrete created by incorporating cellulose nanofibrils (CNFs) can improve the physical properties and increase the durability of pervious concrete. CNFs were added to the concrete mix in proportions ranging from 0.05% to 0.2% by weight of binder. The additions were found to alter matrix rheology. The hydration kinetics of matrix with differing CNF contents were compared and analyzed. The experimental results show the addition of CNFs delayed peak heat flow and maximum cumulative heat. The 28 d compressive strength of pervious concrete increased by up to 26.5% and 28 d flexural strength by up to 25.8% with the addition of 0.05-0.2% CNFs. Addition of 0.1% and 0.2% CNFs increased water permeability. Addition of 0.05-0.15% CNFs decreased mass loss by 73.2-83.7% after 150 freeze-thaw cycles, which corresponded to an increase in frost resistance. Denser matrices and stronger interfacial transition zones were observed using scanning electron microscopy when 0.05-0.2% CNFs were added.

No thermal runaway propagation optimization design of battery arrangement for cell-to-chassis technology

Innovative technology for electric vehicles has been developed in the past years, especially in the design of battery pack. Cell-to-pack (CTP) technology abandoned the conventional module structure and integrated the cell in the pack directly. The next generation Cell-to-chassis (CTC) technology will integrate the battery directly into the chassis fame. How to balance the integration considering both the safety and volume energy density is a challenging task. This paper uses the validated 3D model to investigate the conventional in-line configuration and new proposed brick configuration on thermal runaway propagation (TP) characterization. The in-line module occurs TP while the brick module doesn’t. The analysis of heat flux and heat energy flow among TR battery between adjacent normal batteries points out that the brick module has low peak heat flow and has more battery (heat capacity) to absorb heat, thus the brick can cease TP. In addition, the length of the brick module is optimized to improve the space utilization in CTC fame. Based on not adding thermal barriers, the volume energy density of brick configuration system decreases by less than 3% compare with in-line configuration system. This paper also proves that the structural design can improve the safety of battery system without adding cost.

Effects of dolomite powder on properties of environment-friendly cement asphalt emulsion composites

Cement asphalt emulsion composites (CAEC) are gradually being valued by pavement researchers because of its environment-friendly properties. However, there are still great difficulties in producing high-performance CAEC at present. Dolomite powder (DLM) has been proved in providing promising improvement effects on cement-based materials as an auxiliary cementitious material. Therefore, DLM was introduced into CAEC in this work for the purposes of improving the properties of CAEC. The hydration characteristics, pore structure, mechanical properties, flexural properties, work performance and volume stability of CAEC were thoroughly studied and discussed. Results show that DLM can increase the early hydration rate of cement according to the fact of the left shift of the heat flow peak of CAEC with DLM. However, the increase in the proportion of cement replaced by DLM is the key factor for the reduction of the cumulative hydration heat and the deterioration of the mechanical properties of CAEC. In addition, DLM can reduce the fluidity of CAEC due to its high specific surface area and the apparent angularity surface. Besides, DLM can refine the pore structure and improve the volume stability of CAEC because of the expansion stress provided by brucite and the filling effect of the micro powders. In general, 8%–12% of DLM is recommended as the optimal dosage in CAEC considering the pore structure characteristics, mechanical properties, flexural properties and volume stability of CAEC.

Electrolyte Role on the Thermal Runaway Characteristics of LFP Chemistry

Lithium-ion batteries have become the power source of choice in grid storage applications and electric powertrains, given its high energy density and extended cycle life. However, lithium-ion batteries carry significant safety risks and are a growing hazard due to thermal runaway that can be caused by overheating, cell deformation, overcharging and short-circuits. It is well understood that thermal runaway occurs when the self-heating rate in the cell exceeds the heat dissipation out of the cell. This self-heating is the product of undesired side-reactions in the cell, such as SEI decomposition or oxygen evolution from the cathode, triggered by abuse conditions that then result in thermal runaway. The key to inhibiting thermal runaway is to modify the cell such that the self-heating rate under abuse conditions is significantly reduced.These risks are believed to be mitigated by compromising energy density with safety through the choice of lithium iron phosphate (LFP) as the cathode. LFP is known to demonstrate lower rates of self-heating and achieve lower maximum temperatures during thermal runaway relative to mixed metal oxide cathodes (NMCs). LFP has other reported advantages over NMCs, such as superior cycle life, rate capability, no questionably sourced metals, and significantly lower cost. However, the safety aspect of LFP is only relative to their less stable metal oxide competitors, as LFP cells are still known to evolve oxygen and enter thermal runaway, particularly in larger cells and packs. This concern will increase in the near future as the next obvious battery design choice will be to pair LFP with silicon dominant anodes or lithium metal to create cells with energy densities on par with conventional metal oxide chemistries. There is a need to reduce cell self-heating without further compromising energy density. Therefore our approach is to modify the electrolyte system to reduce the overall cell self-heating rate. This is a tunable, drop-in solution to addressing the need for improving battery safety.We report an alternative electrolyte design to improve the robustness of the SEI and overall stability of the electrolyte system, which carries significance in improving cycle life and abuse tolerance in LFP chemistries in both conventional graphite and silicon-dominant anodes. These electrode pairings are investigated in coin cells, 2 Ah and 30 Ah pouch cells. The choice of electrolyte formulation is shown to impact the abuse tolerance of cells on both the material level, i.e. the electrolyte-electrode interaction and on the cell level.We evaluate the thermal profiles of delithiated LFP paired with lithiated graphite and silicon combined with electrolyte via differential scanning calorimetry (DSC). Our findings suggest that the primary driver of thermal instability in LFP systems arises from the anode in both graphite as well as silicon. The presented electrolyte systems demonstrate reduced overall energy and peak heat flow in the thermal profiles. These findings correlate electrolyte choice with lower self-heating rates in an accelerating rate calorimeter (ARC) heat-wait-seek test on LFP pouch cells. This approach carries significance in not just safer cells but also in enabling next-generation lithium-ion battery technology premised on low-cost cobalt-free cathodes.

Numerical Simulation for Two‐Phase Flow, Heat Transfer, and Inclusion Transport in Bloom Mold Considering the Effects of Argon Gas Injection and Mold Electromagnetic Stirring

A mathematical model based on the Eulerian–Eulerian–Lagrangian method is developed to investigate the two‐phase flow, temperature distribution, and inclusion transport, considering the effect of argon gas injection (AGI) and mold electromagnetic stirring (M‐EMS) in the bloom mold. The magnetic resistance force is adopted to account for the effect of the magnetic field on bubbles. It is demonstrated in the results that when AGI is applied, plumes form near the submerged entry nozzle (SEN) and increase the velocity in the upper part of the mold. While M‐EMS is applied, the swirl flow significantly increases the overall flow velocity and superheat dissipation. In addition, AGI and M‐EMS increase the fluctuation and temperature of the free surface, lower the peak heat flow, and promote inclusions removal. When AGI is applied with M‐EMS, the swirl flow and plumes in the upper part of the mold are weakened due to the interaction between them, and the level fluctuation is lower than that of applying AGI or M‐EMS separately. The heat flow and free surface temperature are more uniform, and the inclusion removal rate further increases. Meanwhile, M‐EMS drives bubble columns to the location between the two ports of SEN and gathers bubbles around the SEN.

Hydration and Properties of Cement in the Belite-Ye'elimite-Ternesite System.

Energy consumption and carbon emissions are lower in the production of belite-ye′elimite-ternesite (C2S-C4A3$-C5S2$, BYT) clinker than Portland cement (PC) clinker. BYT cement can combine the early strength of CSA cements and the durability of belite cements. X-ray diffraction, mercury intrusion porosimetry, isothermal conduction calorimetry and scanning electron microscope were conducted to investigate the hydration process of BYT cement. The hydration products of BYT cement include mainly ettringite, strätlingite and some amorphous AH3 (aluminum hydroxide). Ternesite did prove an early reactivity in BYT cement. The reaction of ternesite with AH3 occurs on the surface of ternesite. Ternesite delays the second heat flow peak of ye′elimite. The strength of BYT cement containing 10% ternesite in the prepared clinker exceeds that of other cement at all ages.

Reaction kinetics of supplementary cementitious materials in reactivity tests

This work characterizes the reaction kinetics of supplementary cementitious materials (SCMs) with calcium hydroxide in the modified R3 test. The heat flow curves of 58 SCMs of varying reactivities were studied. Based on the heat flow curves, the SCMs were classified as more reactive, less reactive, and inert. Most of the heat flow curves in the modified R3 test exhibit, after the peak of heat flow, an initial slow decaying power-law regime that transitions into a longer and faster decaying power-law regime. The pre-exponent of the first regime depends on the initial SCM reactivity and correlates well with the 24-hour heat release in the modified R3 test, thus making it a useful metric for rapid classification of SCMs.

Effect of collapse and hump on thermomechanical behavior in high-power laser welding of 16-mm marine steel EH40

This paper concerns high-power laser welding of thick plates for the ship industry. Thermomechanical behavior during laser welding of 16-mm marine steel EH40 using 25-kW laser power was investigated by a 3D finite element model. The objective is to analyze the effects of weld collapse and hump on the residual stress-induced thermal cycle. A double-cylindrical source model was proposed to simulate the transient distribution of temperature field. Heat flow distribution area is a cylinder, radial heat flow presents a Gaussian distribution, while heat flow peak in the direction of thickness is decaying then increasing exponentially. The predicted weld geometry had good agreement with the actual results. When collapse and hump were considered, simulation error of temperature distribution was only 1.54%. In addition, cooling curves obtained from the thermal simulation were incorporated into the continuous cooling transformation diagram of EH40 to explain the evolution mechanism of microstructure. It was shown that collapse and hump affected the values and distribution trend of residual stress in different thickness, especially in the high gradient stress zone near the weld center. The collapse mainly affects the residual stress distribution on the top surface, while the hump affects that on the bottom surface. Both of them have little influence on the residual stress in the middle thickness area. The cold contraction of weld metal and the stress concentration caused by weld shape during the cooling process are the fundamental reasons that collapse and hump affect the distribution of welding residual stress.

Effect of Ornamental Stone Waste Incorporation on the Rheology, Hydration, Microstructure, and CO2 Emissions of Ordinary Portland Cement.

The ornamental stone industry generates large amounts of waste thus creating environmental and human health hazards. Thus, pastes with 0–30 wt.% ornamental stone waste (OSW) incorporated into ordinary Portland cement (OPC) were produced and their rheological properties, hydration kinetics, and mechanical properties were evaluated. The CO2 equivalent emissions related to the pastes production were estimated for each composition. The results showed that the paste with 10 wt.% of OSW exhibited similar yield stress compared to the plain OPC paste, while pastes with 20 and 30 wt.% displayed reduced yield stresses up to 15%. OSW slightly enhanced the hydration kinetics compared to plain OPC, increasing the main heat flow peak and 90-h cumulative heat values. The incorporation of OSW reduced the 1-, 3-, and 28-days compressive strength of the pastes. Water absorption results agreed with the 28 days compressive strength results, indicating that OSW increased the volume of permeable voids. Finally, OSW incorporation progressively reduced the CO2 emission per m3 of OPC paste, reaching a 31% reduction for the highest 30 wt.% OSW content. Overall, incorporating up to 10 wt.% with OSW led to pastes with comparable fresh and hardened properties as comported to plain OPC paste.

The Effect of Biochar on the Properties of Alkali-Activated Slag Pastes

This paper examines the influence of biochar on the properties of alkali-activated slag pastes using two activator solutions, namely NaOH and Na2CO3. The biochar demonstrated different absorption kinetics in the mixture of slag and the two activator solutions. The pastes with biochar showed a delay in the heat flow peak, compared to the pastes without biochar, but the cumulative heat release in these pastes at later hours was increased, compared to the pastes without biochar. It was found that the use of biochar reduced autogenous shrinkage in the pastes and the reduction in autogenous shrinkage was more pronounced in the alkali-activated slag with NaOH, compared to Na2CO3. The void structure of the pastes was investigated using x-ray micro-computed tomography. It was found that refined pore structure due to reduced effective solution/slag in the pastes with biochar was able to compensate for the decreasing effect of biochar voids on compressive strength. The electrical resistivity was shown to be lower in the pastes with biochar.

Detection of Raised Cloths Characteristics by Heat Flow Using a Miniaturized Warmth and Force Sensor

This paper reports on detection of raised cloths characteristics by a miniaturized warmth and force sensor. In our previous study, it was demonstrated that a warmth and force sensor discriminates block materials by a heat-flow peak in a heat-flow transitional phenomenon. In this study, heat-flow-peak characteristics of the raised cloths with different raising-part lengths were measured, and capability of discrimination of raised cloths was investigated. The experimental results showed that the heat-flow-peak value decreases with increase of the raising-part length when the raising-part length is under 12 mm to 15 mm. The raising-part lengths of the raised clothes were discriminated by the warmth and force sensor.

Isothermal oxidation behavior of heavy crude oil and its low-temperature oxidized oils: Implications for in-situ upgrading of heavy oil

Oxidation of heavy oil is essential for the success of in-situ combustion (ISC) projects. However, the isothermal oxidation behavior of heavy oil has not been well understood. In this work, the static oxidation experiments at temperatures of 80, 120, 160, and 200 °C were conducted to obtain the low-temperature oxidized oils (LTOO). Subsequently, the heat release caused by oxidation reactions of heavy crude oil and its LTOO at temperatures of 100, 200, 300, 400, and 500 °C was thoroughly examined. The results indicated that heavy crude oil was subjected to heat release yielded by low-temperature oxidation (LTO) at 100 °C. At the initial oxidation stage, the peak heat flow at 400 °C for heavy crude oil was obviously greater than that at 500 °C, different from the cases of the other four oxidized oils. For all the heavy oils used, the combustion at 400 °C produced a more lasting thermal effect than that at 500 °C. All the heavy oils used showed similar exothermic behavior at 100 and 200 °C. But at 300 °C, the LTO of the oil oxidized at 160 °C released more heat in comparison with that of the oil oxidized at 200 °C, which was thought to be caused by the saturate and aromatic components present in these two oxidized oils. Compared to the other four heavy oils, the combustion at 400 °C for the oil oxidized at 200 °C released fairly higher heat. However, there were minor differences in the isothermal DSC curves at 500 °C for all the heavy oils, indicating that LTO reactions at temperatures no greater than 200 °C produced negligible influence on heavy oil combustion at 500 °C. For this reason, a reasonable increase in the ignition temperature was recommendable when achieving ISC of heavy oils with deep LTO degrees and ultra-heavy oils.

Performance study of a phase change material Trombe wall system in summer in hot and humid area of China

In order to reduce the impact of daytime climate fluctuation on the performance of the Trombe wall system (TWS) and enhance its ventilation and cooling effect in summer, an improved phase change material (PCM) TWS was constructed in this study. In this paper, the thermal performance of the PCM TWS was evaluated by comparative experiments in hot and humid area of China in summer. The findings demonstrated that the PCM TWS provided more effective heat insulation than the common envelope and the typical TWS. During the day the PCM cold storage plate released the cooling capacity with a peak heat flow rate of - 25.1w/m2 and it accumulated cold energy with a peak heat flow rate of 20.1w/m2 during the night. The PCM TWS achieves better induced ventilation than the typical TWS, corresponding to a maximum room ventilation rate of 140m3/h (31h−1) and a minimum value of 29m3/h (6 h−1). The PCM TWS can significantly lower the indoor air temperature to a maximum of 2.1 °C compared to the typical TWS and 5 °C compared to the ordinary envelope.

Thermo-Physiological Comfort Properties of Sportswear with Different Combination of Inner and Outer Layers.

Consumers expect high-performance functionality from sportswear. To meet athletic and leisure-time activity requirements, further research needs to be carried out. Sportswear layers and their specific thermal qualities, as well as the set and air layer between materials, are all important factors in sports clothing. This research aims to examine the thermal properties of sports fabrics, and how they are affected by structure parameters and maintained with different layers. Three inner and four outer layers of fabric were used to make 12 sets of sportswear in this study. Before the combination of outer and inner layers, thermal properties were measured for each individual layer. Finally, the thermal resistance, thermal conductivity, thermal absorptivity, peak heat flow density ratio, stationary heat flow density, and water vapor permeability of bi-layered sportswear were evaluated and analyzed. The findings show that sportswear made from a 60% cotton/30% polyester/10% elastane inner layer and a 100% polyester outer layer had the maximum thermal resistance of 61.16 (×103 K·m2 W−1). This performance was followed by the sample made from a 90% polyester/10% elastane inner layer and a 100% polyester outer layer, and the sample composed of a 100% elastane inner layer and a 100% polyester outer layer, which achieved a thermal resistance value of 60.41 and 59.41 (×103 K·m2 W−1), respectively. These results can be explained by the fact that thicker textiles have a higher thermal resistance. This high-thermal-resistance sportswear fabric is appropriate for the winter season. Sportswear with a 90% polyester/10% elastane inner layer had worse water vapor resistance than sportswear with a 60% cotton/30% polyester/10% elastane and a 100% elastane layer. Therefore, these sports clothes have a higher breathability and can provide the wearers with very good comfort. According to the findings, water vapor permeability of bi-layered sportswear is influenced by geometric characteristics and material properties.

Combustion Behavior and Kinetics Analysis of Isothermal Oxidized Oils from Fengcheng Extra-Heavy Oil

The low-temperature oxidation (LTO) of heavy oil is of great significance for the combustion front stability, which directly influences the efficiency and safety of in-situ combustion (ISC). To provide feasible heating by artificial ignition before the implementation of ISC in the Xinjiang Fengcheng (FC) oilfields, this paper investigates the oxidation behavior of FC extra-heavy oil and its isothermal oxidized oils. Firstly, FC extra-heavy oil was subjected to isothermal oxidation experiments conducted utilizing an oxidation reactor, and the physical properties of the gaseous products and oxidized oils were analyzed. The combustion behavior of the FC extra-heavy oil and oxidized oils was then studied by non-isothermal thermogravimetry and differential scanning calorimetry. Subsequently, the Friedman and Ozawa–Flynn–Wall methods were adopted to perform kinetic analysis. Oxygen consumption was always greater than the production of CO and CO2, so oxygen addition reactions were the main pathway in heavy oil LTO. H/C decreased to 8.31% from 20.94% when the oxidation temperature rose from 50 °C to 150 °C, which deepened the oxidation degree. The density and viscosity of 200 °C to 350 °C oxidized oils increased at a slower rate, which may be related to the LTO heat effect. The change law of temperature interval, peak temperature, and mass loss of the oxidized oils had a good correlation with the static oxidation temperature. Compared with other oxidized oils, the peak heat flow and enthalpy of 350 °C oxidized oil increased significantly with high-temperature combustion, and were 42.4 mW/mg and 17.77 kJ/mol, respectively. The activation energy of 350 °C oxidized oil began to decrease obviously around a conversion rate of 0.4, which indicates that it was beneficial to coke deposition with stronger activity. Finally, we came up with LTO reaction mechanisms and put forward a reasonable preheating temperature for the application of ISC in FC oilfields.

Influence of wall thermal performance on the contribution efficiency of the Phase-Change Material (PCM) layer

Integrating Phase-Change Material (PCM) in building walls has been an effective technological method to improve wall thermal performance, but its contribution efficiency has been impacted by the thermal performance of original walls. To explore the influence laws of wall thermal performance on the contribution efficiency of the PCM layer and then find the suitable application of the PCM layer, the numerical simulation verified by an experiment was done for wall physical models with different thermal performance. Experimental results revealed that the temperature amplitudes of the inner surface and indoor air were reduced by 25.13 °C and 20.86 °C respectively due to adding the PCM layer in the light-weight building models. Numerical results showed integrating the PCM layer increased the time lag, but this contribution efficiency had the poor correlation with the heat transfer coefficient and the thermal inertia. Moreover, the contribution efficiency from the PCM layer would be increased on the decrement factor and the peak heat flow with an increase of the heat transfer coefficient or reducing the thermal inertia. The core contribution from the PCM layer is not thermal insulation improvement, but thermal adjustment enhancement and thereby, the contribution of integrating the PCM layer was ignored on the average heat flow.

Utilization of Thermally Treated SiC Nanowhiskers and Superplasticizer for Cementitious Composite Production.

Nanomaterials are potential candidates to improve the mechanical properties and durability of cementitious composites. SiC nanowhiskers (NWs) present exceptional mechanical properties and have already been successfully incorporated into different matrices. In this study, cementitious composites were produced with a superplasticizer (SP) and 0–1.0 wt % SiC NWs. Two different NWs were used: untreated (NT-NW) and thermally treated at 500 °C (500-NW). The rheological properties, cement hydration, mechanical properties, and microstructure were evaluated. The results showed that NWs incorporation statistically increased the yield stress of cement paste (by up to 10%) while it led to marginal effects in viscosity. NWs enhanced the early cement hydration, increasing the main heat flow peak. NWs incorporation increased the compressive strength, tensile strength, and thermal conductivity of composites by up to 56%, 66%, and 80%, respectively, while it did not statistically affect the water absorption. Scanning electron microscopy showed a good bond between NWs and cement matrix in addition to the bridging of cracks. Overall, the thermal treatment increased the specific surface area of NWs enhancing their effects on cement properties, while SP improved the NWs dispersion, increasing their beneficial effects on the hardened properties.

Permian geothermal units in the Sichuan Basin: Implications for the thermal effect of the Emeishan mantle plume

The Emeishan mantle plume is supposed to play an important role in the Permian thermal regime and source rock hydrocarbon generation evolution in the Sichuan Basin, Southwest China. In this paper, we provide new valuable insights into the spatial thermal effect of the Emeishan mantle plume to the Sichuan basin and maturity evolution of the Paleozoic source rocks. Cambrian core samples from four wells were selected for zircon fission track and zircon (U–Th)/He analysis in order to determine their thermal histories. Then the thermal histories of typical wells throughout the basin were obtained based on the above result and previous studies. According to the peak heat flow value (q), four Permian geothermal units were classified: a stratospheric heat flow unit (q ≥ 90 mW/m2), a high heat flow unit (80 ≤ q < 90 mW/m2), a medium heat flow unit (70 ≤ q < 80 mW/m2), and a normal heat flow unit (q < 70 mW/m2). The interpretation of the abnormal Permian heat flow indicates that the enormous heat flow anomalies with values of >20 mW/m2 occurred in the stratospheric and high heat flow units was mainly caused by the mantle plume, while the weak Permian thermal perturbation with heat flow anomalies of <15 mW/m2 in other two units was more likely associated with crustal thinning. The thermal effect of the Emeishan mantle plume may be contained within the stratospheric and high heat flow units. By comparing the maturation histories of the Paleozoic source rock, we identified the thermal effect on the maturity evolution. The thermal perturbation had no obvious impact on the maturity evolution of the Lower Permian and Lower Silurian Longmaxi Formation. Only the Lower Cambrian Qiongzhusi Formation within high geothermal unit suffered significant thermal effect of the mantle plume and matured rapidly during the end of the Early Permian.