Combustion Behavior Research Articles

The effect of organophosphorus flame retardants on the combustion behavior and performance of poly (methyl methacrylate)

Maintaining transparency poses a challenge in the preparation of flame-retardant poly (methyl methacrylate) (PMMA). The feasibility of preparing flame-retardant transparent PMMA by incorporating oligomeric resorcinol bis(diphenylphosphate) (liquid), 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and hexaphenoxycyclotriphosphazene (solid) as additives has been explored. The impact of the flame retardants on the processing performance, thermal stability, combustion behavior and mechanical properties of PMMA has been investigated. The presence of organophosphorus compounds does not impact the transparency of PMMA and has a significant plasticizing effect. The modified PMMA displays a UL94 V-2 rating largely due to the formation of noncombustible droplets. However, the blend exhibits lower heat resistance, modulus and strength than does unmodified PMMA. The presence of organophosphorus compounds induces a higher limiting oxygen index (LOI) and reduced heat release for combustion of the blends than observed for PMMA without relying on charring, among which DOPO has a higher flame retardant efficiency due to its higher phosphorus content and lower decomposition temperature.

Upgrading Carthamus by HTC: Improvement of Combustion Properties

This study investigated the fuel potential and combustion behavior of hydrochars derived from a unique precursor: Carthamus pomace. Initially, the hydrothermal carbonization process of this novel feedstock was examined across various temperature ranges (180–240 °C) and durations (15–180 min). The impact of these processing conditions was analyzed in terms of degradation mechanisms and their correlation with the resulting properties of the hydrochars (HCs) produced. Then, the combustion performance of these materials was studied by means of thermogravimetry, and the differences in reactivity and activation energy were analyzed and associated with preparation processes. Finally, the most promising HTC parameters were identified and a thermoeconomic study on the use of selected HCs on a thermal plant devoted to the production of electricity was evaluated including energy savings associated with the implementation of heat exchangers using the heat of the flue gases to partially supply the energy needs associated with HTC.

Exploring electric field forces and polarization influence on combustion in Fe-additive fuel droplets

The application of electrical techniques such as electric field, polarization, and ionization in the field of combustion makes many positive developments possible. The electric field effect offers significant advantages in controlling flame stability and reducing soot formation during the combustion of fuels. Also, the conditioning effect can improve particle oxidation during combustion for hydrocarbon fuels containing metal particle inclusions with high calorific value. This study focuses on investigating the combustion and atomization behavior of Fe additive diesel fuel droplets at electric field strengths of E = 5 V/m, E = 6.7 V/m, and E = 10 V/m and in positive (↑) and negative (↓) electric field directions. The experiments were carried out by igniting a fuel droplet suspended on a ceramic wire with an arc at the center of the electric field between two conductive plates in a combustion chamber with optical apertures. The combustion processes were recorded with an optical system consisting of a high-speed camera and a thermal camera. Combustion and atomization behavior were characterized by sequential flame and droplet atomization images, respectively. The droplet shape change and flame behavior results were comparatively evaluated according to the d2-law. Ignition delay and extinction times were determined by processing threshold technique and maximum flame temperatures were determined by processing thermal camera images. The results showed that increasing the electric field intensity in the negative electric field direction resulted in improved soot oxidation, and Fe particles burnt efficiently. Ignition delay times showed a decreasing trend with an electric field effect and an increasing trend with the addition of Fe particles. The highest maximum flame temperature and lowest extinction time were recorded as 785 K and ∼ 578.34 ms for Diesel/Fe/100(↓) fuel droplet, respectively and Fe particles did not exhibit microexplosion phenomena at E = 10 V/m. In this study, it has been shown that an effective oxidation can be achieved for Fe particles by increasing the mobility of ionized species in the flame zone under the effect of electric field and a homogeneous thermal field can be created in the flame zone even in fuels with particle addition at increasing electric field intensities.

Theoretical and kinetic study of the hydrogen abstraction reactions of ethyl propionate

Ethyl propionate shows great promise as a biodiesel molecule model. However, the current oxidation kinetic model falls short in accurately predicting its combustion behavior. Therefore, this study employed ab initio quantum chemistry methods to analyze the hydrogen abstraction reactions of ethyl propionate with various reactive radicals, including OH, O, H, CH3, C2H3, C2H5, HO2, CH3O and CH3O2, which play a critical role in refining the oxidation kinetics. Theoretical calculations were conducted to determine the rate constants and branching ratios for these reactions at temperatures ranging from 500 K to 2500 K using transition state theory, quasi-rigid rotor harmonic oscillator model, and tunneling correction. After updating the kinetics of hydrogen abstraction reactions in the oxidation mechanism proposed by Metcalfe et al., the modified model was validated by comparing the simulated mole fraction evolutions of ethyl propionate and major products in a jet-stirred reactor, ignition delay in a closed homogeneous batch reactor, and laminar flame speed with experimental data. The findings indicate that the modified model reliably reproduces the experimental data and significantly improves the prediction accuracy for low-temperature combustion of ethyl propionate when compared to the original model.

The mechanism of the influence of radiation heat flux on the combustion behavior of raw rubbers

Understanding the combustion behavior of rubbers is crucial for predicting their fire hazards. The cone calorimeter experimental results in this study confirm that the combustion behavior of raw rubbers depends on the rubber type and the heat flux. Natural rubber and ethylene-propylene-diene monomer rubber exhibit heat release rate (HRR) curves with only one peak at the end of the burning stage under all tested heat fluxes. At higher heat fluxes, the HRR curves of polybutadiene rubber (BR) and styrene butadiene rubber (SBR) exhibit a single peak; at heat fluxes lower than 20 kWm−2, two HRR peaks were observed. The proposed mechanism model with the crosslink reaction as the key factor can explain the emergence of two-peak HRR curve and has been proved through experiments and simulations. For BR and SBR at 15 kWm−2, the specimens exhibit two upper layers at ignition time. The surface pyrolysis layer seems to be covered by black film or char, with the crosslink degree as high as 84.23–100 %. The second crosslink reaction layer exhibits a higher decomposition temperature Td,5 % than the original rubber. Based on reaction kinetics and thermodynamics data derived from TG/DSC experiments, the novel pyrolysis model taking crosslink reaction and thermal decomposition of crosslinked intermediate into account well predicts the HRR curves obtained at varied heat fluxes. The conversion of raw rubber to the crosslinked intermediate plays an important role in the reduction of HRR immediately after ignition, resulting in the first HRR peak.

Insight into energy release characteristics of TiH2 dust explosion through ignition experiments and molecular dynamic simulations

TiH2 is an efficient hydrogen storage material with high energy density and relatively stable chemical quality, which is commonly used in metal sponge production, hydrogen storage, battery technology, rocket propellants, etc. In this study, TiH2 dust explosion is systematically investigated by integrating ignition experiments with reactive force field molecular dynamics simulation. Findings show that when the TiH2 dust concentration is 750 g·m−3, both the explosion pressure and explosion pressure rise rate reach their maximum values under airtight and venting conditions. There are three stages in the whole combustion process: the combustion development stage, the stable combustion stage, and the decay stage. The flame length (L) and flame propagation velocity (v) grow with the increase of dust concentration. TiH2 dust explosion with different concentrations in macroscopic tests is approximated by simulating the combustion behaviors of the TiH2 system with different densities. The combustion reaction rate of TiH2 grows with an increase in system density, and the simulation results are consistent with experimental findings.

Silica-Containing Phosphorus-Based Sol-Gel Finishing to Improve Flame Retardant Performance of Cotton Fabrics

In this paper, the sol-gel technique was used to design hybrid phosphorus-doped silica structures for improving the thermal stability and flame retardancy of cotton fabrics. To this aim, diethylphosphatoethyltriethoxysilane (DPTS) was employed as phosphate alkoxysilane in a multistep procedure that involved multiple layers (from 1 to 6) depositions. The multi-layer coatings were applied by padding using sols containing appropriate molar ratios of the precursor, anhydrous ethanol, catalyst, and hydrochloric acid. Moreover, the synergism P-N on flame retardancy of cotton was assessed by introducing 3-aminopropyltriethoxysilane (APTES) as an N-donor precursor in DPTS sols. The effects of the catalyst during the alkoxide reaction and the silica amount applied by sol-gel treatment on the thermo-oxidative behavior of the treated fabrics were deeply studied. The creation of the silica skeleton on the cotton surface and the interactions between the cellulosic fibres and the doped layer were investigated using FT-IR ATR spectroscopy. Moreover, thermal and thermo-oxidative stability, flammability properties, and combustion behavior of the sol-gel treated cotton fabrics were also studied, proving the effectiveness of the sol-gel coating in the fire protection of the cellulosic substrate.

Direct numerical simulation of ammonia/n-heptane dual-fuel combustion under high pressure conditions

Ammonia (NH3) combustion has received increasing attention for its carbon-free nature. However, the utilization of ammonia in engines is constrained by its relatively low reactivity. To overcome this shortcoming, ammonia blending with high-reactivity fuels has been used. In the present work, direct numerical simulation (DNS) of ammonia/n-heptane dual-fuel combustion was performed to understand the effects of ammonia addition on the combustion behavior of n-heptane sprays. Three DNS cases with NH3 energy ratios of 0%, 20%, and 40% were considered. Two-stage combustion was observed in all cases. It was found that both the first-stage and second-stage ignition delay times increase with increasing NH3 energy ratio, and the peak of mean heat release rate (HRR) reduces with increasing NH3 energy ratio. For low-temperature combustion, ignition kernels were observed in the case with pure n-heptane while ignition occurs almost volumetrically in the cases with NH3 addition. The reaction zone of the cases with NH3 addition is thicker compared to that of the case with pure n-heptane. The reactions of NH3 involve radicals, such as OH, which affects the low-temperature combustion of n-heptane. In the stage of high-temperature combustion, individual ignition kernels with significant heat release rate were observed in the cases with NH3 addition, where the reaction zones are thin. In contrast, for the case with pure n-heptane, large heat release rate occurs simultaneously over the entire domain with thick reaction zones. Ignition occurs in regions characterized by low scalar dissipation rate for both low-temperature and high-temperature combustion in all cases. It was found that, though the contributions of NH3-related reactions to the total HRR are noticeable, the contributions of important elementary reactions to the total HRR in pure n-heptane combustion still prevail in the cases with NH3 addition, which indicates that n-heptane chemistry dominates that of NH3 in this work.

Property Enhancement of Waste Printed Circuit Boards Powders Reinforced Polypropylene by In Situ Magnesium Hydroxide Impregnation from Waste Lye.

Using alkali pretreatment can effectively remove residual variable-valence metals from non-metallic powder (WPCBP) in waste printed circuit boards. However, substantial amounts of waste lye are generated, which causes secondary pollution. On this basis, this study innovatively utilized waste alkali lye to prepare nano-magnesium hydroxide. When the dispersant polyethylene glycol 6000 was used at a dosage of 3 wt.% of the theoretical yield of magnesium hydroxide, the synthesized nano-magnesium hydroxide exhibited well-defined crystallinity, good thermal stability and uniform particle size distribution, with a median diameter of 197 nm. Furthermore, the in situ method was selected to prepare WPCBP/Mg(OH)2 hybrid filler (MW) and the combustion behavior, thermal and mechanical properties of PP blends filled with MW were evaluated. The combustion behavior of the PP/MW blends increased with the increasing hybrid ratio of Mg(OH)2, and the MW hybrid filler reinforced PP blends showed better thermal and mechanical properties compared to the PP/WPCBP blends. Furthermore, the dynamic mechanical properties of the PP/MW blends were also increased due to the improved interfacial adhesion between the MW fillers and PP matrix. This method demonstrated high economic and environmental value, providing a new direction for the high value-added utilization of WPCBP.

Analyzing Burner Performance and Combustion Phenomenon in an Olefin Plant's Industrial Furnace: A CFD Study.

This work presents a comprehensive study of the combustion performance of an industrial furnace in an olefin plant using computational fluid dynamics (CFD) simulations. The focus was on analyzing the heat release pattern of bottom burners to optimize the furnace efficiency in steam-cracking processes. The study developed an accurate computational fluid dynamics (CFD) model for predicting combustion behavior in a cracking furnace. The computational model was validated by comparing the simulation results with industrial data and was used to investigate the impact of burner clogging and the importance of small holes in the body of burners in the furnace. The results also provided insights into the influence of excess air, temperature distribution, fluid behavior, composition of combustion products, and thermal efficiency of the furnace. The presented results contributed to a better understanding of parameters controlling combustion performance in steam-cracking furnaces.

Feasibility of co-disposal of lignite and eucalyptus wood in coal-fired power plants: thermogravimetric characterization, typical gaseous pollutant emission characteristics, and economic analysis

ABSTRACT Energy issues are becoming increasingly prominent, and biomass blending in coal-fired power plants can improve combustion performance and reduce gaseous pollutant emissions, thereby improving economic efficiency. In this study, a thermogravimetric analyzer, a horizontal tube furnace, and an infrared flue gas analyzer were used to investigate the combustion behavior and gaseous pollutant emissions of the co-combustion of LC and EW. The results show that blending EW into LC cofiring can inhibit the release of volatile matter and promote the decomposition of fixed carbon and lignin simultaneously. The HHV of EW (15.88 MJ/kg) reaches 63.7% of LC’s (24.90 MJ/kg), indicating EW has a high energy utilization value. With increasing combustion temperature, the average value of CR S increased from 47.09% to 59.94%, and the average value of CR Cl increased from 26.15% to 52.15%, leading to a significant increase in SO2 and HCl emissions. The decrease in combustion temperature slightly promoted the release of N (CR N increased from 11.76% to 14.45%). The results of the economic analysis show that the cost of CaO and NH3·H2O used for removing gaseous pollutants decreased the most, and the economic efficiency increased the fastest to 14,000 RMB/day when the EW blending ratio increased from 10% to 20%.

Experimental study on flow characteristics and burning behavior for fire of flammable gases leakage underwater

The occurrence of subsea pipeline leakage incidents has gradually increased with the rapid development of the offshore oil and gas industry. Research on the fire dynamics of flammable gases leakage underwater is very limited, particularly in understanding the coupling mechanism of flow and combustion on the water surface. This paper presents a systematical investigation on flow characteristics and burning behavior for fire of flammable gases leakage underwater. A series of laboratory-scale fire behavior experiments were conducted through a self-designed experimental platform, consisting of the leakage control module, water tank and measurement apparatus. It was revealed that the leakage flow rate and water depth would influence the flow characteristics and burning behavior significantly. Two different burning conditions were found for the flame burning above the water surface (FBWS), i.e., the stable and self-extinguishing (unstable) burning states. The dimensionless analysis is conducted for the burning conditions, where the critical criterion is developed to distinguish the stable and unstable burning states. The base diameter of stable FBWS is almost 1.6 times of the diameter of bubble plume on the water surface. The flame pulsation frequency and dimensionless flame height (the ratio of height to base diameter of flame) of the stable FBWS are different from thoes of liquid pool fires and gas diffusion fires. Consequently, a correlation between the Strouhal number and the Froude number is correlated. Finally, the correlation between the dimensionless flame height and the dimensionless heat release rate is proposed for the stable FBWS.

Experimental and numerical investigations on fire development in a timber-based compartment with identification of characteristic events

An experiment and numerical simulations were carried out to investigate the mechanism of the incipient and growth stages of a building fire. The building, constructed in the 1980s with wooden components, has one compartment and one opening. The average fire load density was 1495.3 MJ/m2, including the wooden columns, beams, furniture, etc. The evolution of indoor temperature, gas concentration, gas flow rate and burning behaviors were obtained and analyzed. To better understand the fire development process, we identified characteristic events, including pilot fire, incipient fire, pre-flashover fire spread, ceiling jet period, and flashover and spill plume. By defining dimensionless time (τ = ti/tflashover), it was found that the fire development process simulated by Fire Dynamic Simulator experienced the same characteristic events as the experiment. In this work, when flashover occurred, the neutral plane height decreased to about half the height of the opening, the velocity of hot smoke outflow was higher than 3 m/s, and the maximum thickness of the wood charred layer reached 1 cm. Two theoretical methods to estimate the heat release rate (HRR) in the fuel-controlled stage before flashover were proposed. The HRRs at the time of flashover with the two methods are at the same order of 5 MW, and the error between them was within 18.1%, which verifies the feasibility of the above methods to a certain extent. This study helps to learn the characteristics of early and growth stages of building fires with wooden components.

Evaluation of physicochemical properties and combustion behavior of biomass refuse-derived fuel

Recently, a 125 MW biomass power plant in South Korea has been operating annually using 600,000 tons of wood pellets as fuel, producing approximately 6,000 tons of biomass refuse-derived fuel (BRDF) each year. Owing to challenges in pulverizing biomass, large particles are introduced into the boiler furnace during power generation. However, their size hinders complete combustion, and approximately 1.0 % of the fuel input to the boiler descends to the bottom and is subsequently collected in the ash hopper; it corresponds to BRDF. This study evaluated the recyclability and applicability of BRDF in boilers by comparing its fuel properties with those of raw wood pellets (RWP), torrefied wood pellets (TWP), and coal. Furthermore, we analyzed and assessed the physicochemical properties and fundamental combustion characteristics using the thermally treated biomass grindability index (TTBGI), Fourier-transform infrared spectroscopy (FT-IR), and thermogravimetric analysis (TGA). The fixed carbon content of BRDF increased, whereas the volatile matter content decreased compared with that of RWP. The H/C and O/C atomic ratios of BRDF were similar to those of coal, and the higher heating value (HHV) of BRDF was improved compared with the other samples. Scanning electron microscopy (SEM) images confirmed significant pore development in the BRDF, and BET analysis indicated an increase in the specific surface area. The TTBGI measurements indicated improved grindability of the BRDF and increased lignin content. In particular, Cmean (%/min) and Cmax (%/min) increased compared with RWP, and the combustion characteristics of the BRDF improved. Therefore, this study suggests that BRDF has the potential to be utilized as a fuel in existing boilers.

Near-Infrared Spectroscopy Modeling of Combustion Characteristics in Chip and Ground Biomass from Fast-Growing Trees and Agricultural Residue

This study focuses on the investigation and comparison of combustion characteristic parameters and combustion performance indices between fast-growing trees and agricultural residues as biomass sources. The investigation is conducted through direct combustion in an air environment using a thermogravimetric analyzer (TGA). Additionally, partial least squares regression (PLSR)-based models were developed to assess combustion performance indices via near-infrared spectroscopy (NIRS), serving as a non-destructive alternative method. The results obtained through the TGA reveal that, specifically, fast-growing trees display higher average ignition temperature (227 °C) and burnout temperature (521 °C) in comparison to agricultural residues, which exhibit the values of 218 °C and 515 °C, respectively. Therefore, fast-growing trees are comparatively difficult to ignite, but sustain combustion over extended periods, yielding higher temperatures. However, despite fast-growing trees having a high ignition index (Di) and burnout index (Df), the comprehensive combustion performance (Si) and flammability index (Ci) of agricultural residue are higher, indicating the latter possess enhanced thermal and combustion reactivity, coupled with improved combustion stability. Five distinct PLSR-based models were developed using 115 biomass samples for both chip and ground forms, spanning the wavenumber range of 3595–12,489 cm−1. The optimal model was selected by evaluating the coefficients of determination in the prediction set (R2P), root mean square error of prediction (RMSEP), and RPD values. The results suggest that the proposed model for Df, obtained through GA-PLSR using the first derivative (D1), and Si, achieved through full-PLSR with MSC, both in ground biomass, is usable for most applications, including research. The model yielded, respectively, an R2P, RMSEP, and RPD, which are 0.8426, 0.4968 wt.% min⁻4, and 2.5; and 0.8808, 0.1566 wt.%2 min⁻2 °C⁻3, and 3.1. The remaining models (Di in chip and ground, Df, and Si in chip, and Ci in chip and ground biomass) are primarily applicable only for rough screening purposes. However, including more representative samples and exploring a more suitable machine learning algorithm are essential for updating the model to achieve a better nondestructive assessment of biomass combustion behavior.

Co-pyrolysis model for polylactic acid (PLA)/wood composite and its application in predicting combustion behaviors

Polylactic acid (PLA)/wood composite has gained great popularity in applications due to its renewable and biodegradable features, whereas quantitative modelling from microscale co-pyrolysis to bench-scale combustion was barely reported. To challenge this issue, poplar wood, PLA and three PLA/wood composites with mass ratios of 1:3, 1:1, and 3:1 were adopted to conduct thermogravimetric analysis (TGA) and cone calorimeter tests. A numerical model was utilized to examine the interaction between wood and PLA during co-pyrolysis. Kinetics and temperature-dependent thermodynamics of each component were determined by inversely modelling some specific experimental results, while the remaining data were used for model validation. Effective heats of combustion of gas products were estimated by fitting the recorded heat release rates (HRR) in combustion tests. The results showed that PLA/wood composites considerably reduced the peak temperature of co-pyrolysis by 21.7–23.7 K compared to neat PLA. Pyrolysis of wood and PLA could be described by a four-component reaction scheme and a single-step reaction, respectively, whereas two additional reactions were needed to quantify the interaction between PLA and wood. Three methods were used to predict the measured HRRs, and all calculated curves fitted the experimental results well. PLA/wood composites decelerated the thickness regression rate and prolonged the combustion time. Meanwhile, measured CO and CO2 production rates were thoroughly analyzed.

Investigation of Flame Structures of Double-Base Propellant and Modified Double-Base Propellant Containing Nitramine Using OH-PLIF and Kinetic Simulation.

The combustion behavior of various propellant samples, including double-base propellants, pressed nitramine powders, and modified double-base propellants containing nitramine, was examined using OH-PLIF technology. The combustion process took place within a combustion chamber, and images capturing the flame at the moment of stable combustion were selected for further analysis. The distribution and production rate of OH radicals in both the double-base propellant and the nitramine-modified double-base propellant were simulated using Chemkin-17.0 software. The outcomes from both the experimental and simulation studies revealed that the concentration of OH radicals increased with a higher content of NG in the double-base propellant. In the modified double-base propellant containing RDX, the OH radical concentration decreased as the RDX content increased, with these tendencies of change aligning closely with the simulation results.

Upgrading of cow manure by hydrothermal carbonization: Evaluation of fuel properties, combustion behaviors and kinetics

The rational thermochemical conversion of livestock manure holds significant implications for the recovery and utilization of wastes. In this study, cow manure (CM) was treated by hydrothermal carbonization (HTC) to evaluate the fuel properties, combustion behavior and kinetics of hydrochars. The results showed that HTC increased the carbon content of CM from 37.02% to 43.68% and the H/C and O/C ratios comparable to lignite. The oxygen-containing functional groups of hydrochars decreased and displayed typical deposition micromorphology of secondary char. For aqueous phase, furans and phenols were enriched at 200 °C and 260 °C respectively, which were the main precursor or/and components of secondary char. The thermogravimetric analysis displayed hydrochars combustion were more stable and lasting. The secondary char reduced ignition temperature, but limited impact on volatilization during combustion. Compared with CM, hydrochars showed lower activation energy in initial combustion, and higher at high conversions (except for CM260). The relative lower activation energy of CM260 was mainly attribute to the loose ash structure. Besides, HTC could alleviate slagging/fouling of CM combustion and high temperature strengthened the effect. These results indicate that HTC is a promising approach to treat CM for solid fuels, and 240 °C is suggested to upgrading the characteristics.

Effects of Ramp-Induced Incident Shock Impingement Under Various Slope Angle Configurations in a Strut-Based/Cavity-Assisted Supersonic Combustor

ABSTRACT The present study conducts a numerical investigation into the effects of ramp-induced shock impingement with different opening angles on the global flow-field and combustion behaviors within a strut-based/cavity-assisted scramjet combustor. To reproduce the intricate physical phenomena and all inflow properties of the primary channel, two-dimensional Reynolds-averaged Navier–Stokes (RANS) equations integrated with the shear stress transport (SST) k − ω turbulence model is implemented. The current approach considers several slope angle configurations of the ramp since they generate various shock systems that differ in magnitudes and coherent structures, substantially affecting the combustion efficiencies and chemical species distributions. Results reveal that an optimal shock angle of the ramp in correspondence with the current operating conditions can be achieved at 20°, which increases the combustion efficiency by 11% at the end of the cavity trailing edge without provoking excessive loss of total mass-flux-weighted pressure recovery. However, further expanding the slope angle above the optimum will trigger the flow blockage mechanism which enlarges the recirculation region on both sides of the ramp, simultaneously initiate their local thickening processes and create shock train areas owing to intensive interactions with the turbulent boundary layers. These phenomena are known for decreasing the total pressure ratio, adversely affecting all performance metrics of interest and destabilizing the main channel flow path.

Developments in the RCCI engines powered by several alternative fuel types: An overview

The perspective on internal combustion engines (ICEs) has changed because of the step-by-step decrease in oil reserves, environmental concerns, and many other reasons. However, the use of these engines will continue in the coming years. The development of ICEs has accelerated in recent years. As a result, studies on systems that can improve performance and reduce pollution in engines are carried out by many researchers. The basis of the studies carried out in this context is the change in the combustion mode. In other words, the emergence of different combustion modes is given importance by researchers. Among these, many studies have been made on the implementation of the reactivity-controlled compression ignition (RCCI) combustion mode. RCCI engine uses two different fuels. These fuels are low-reactivity (alcohol, gasoline, etc.) and high-reactivity (diesel, biodiesel, etc.) fuels. In addition, the fact that different alternative fuel types can be employed in these engines has made them popular all over the world. This review presents the results of the effects of parameters such as fuel ratio, different injection strategies, exhaust gas recirculation (EGR) rate, compression ratio, and piston geometry on the performance, emissions, and combustion behavior of RCCI engines using both conventional and alternative fuels. This study has been compiled to provide an overview of the current status of the RCCI concept and to offer benefits to researchers.