Fuel Regression Rate Research Articles

The decoupled effect of oxidizer mass flux and combustion pressure on turbulent combustion characteristics of finite-length solid fuel

Combustion pressure and oxidizer mass flux are key factors influencing the performance of hybrid rocket motors. In the present work, the decoupled effects of oxidizer mass flux and combustion pressure on turbulent combustion characteristics were investigated. First, a finite-length combustion theory of fuel grains was developed to identify the main sensitive parameters, including flame structure and the recirculation zone, which affect the combustion of solid fuel. Then, a two-dimensional transient numerical model, based on the coupling characteristics of the heat transfer process in solid fuel grains and dynamic combustion flow, was developed and validated through fire experiments under a wide range of inflow conditions. A quantitative analysis was conducted to assess the impact of flame structure and the recirculation zone on the dynamic combustion characteristics of finite-length solid fuel. The results showed that the fuel characteristic temperatures of the front and central parts are negatively correlated with flame height, while the characteristic temperature of the rear part is positively correlated with the recirculation zone temperature. Both the mass flow rate and combustion pressure are negatively correlated with flame height and positively correlated with the temperature of the recirculation zone. Compared to combustion pressure, the influence of mass flow rate is more significant. The transient processes of the solid fuel regression rate under different inflow conditions exhibit a consistent tendency: an increase in mass flow flux and combustion pressure results in faster attainment of peak regression rate and stabilization.

Numerical Study on the Unsteady Behavior of the Solid-Fuel Scramjet

The unsteady evolution of the flowfield in a solid-fuel scramjet is investigated. The researchers approximate the continuous working of the solid-fuel scramjet via stand-alone geometries. These directly correspond to the actual shapes of the combustor recorded during experimental tests of the engine. The flow is modeled using the compressible Navier–Stokes and species transport equations and the shear stress transport k−ω turbulence model. A two-dimensional axisymmetric formulation is employed. The fuel is the polymer polymethyl methacrylate. The integral parameters of the combustor are computed in the simulations using nonvarying geometries at discrete instants. These values are then compared with measurements taken at the same instant during the continuous working of the engine in experimental tests. The good agreement during the whole process demonstrates the permanent quasi-steadiness nature of the fluid flow in relation to the varying combustor shape. The discussion analyzes the evolution of critical combustor parameters, including thrust, fuel regression rate, and various efficiencies, and correlates them with the underlying flow variables. The findings provide valuable insights into the unsteady development of the flow physics within the combustor of a solid-fuel scramjet, contributing to a better understanding of this complex system.

Catalytic effects of transition metal oxides on HTPB-based fuel polymer matrices

Low regression rate due to difficult pyrolysis is a major challenge in the practical application of terminated hydroxyl‑terminated polybutadiene (HTPB)-based fuels in hybrid rocket propulsion. Accelerating the decomposition of the polymer matrix is an effective method to improve the regression rate of HTPB fuels. To determine the difference in combustion performance between different transition metal oxides loaded HTPB-based fuels, nickel oxide (NiO), ferric oxide (Fe2O3), copper oxide (CuO) and manganese dioxide (MnO2) were introduced into the HTPB matrix at 5% mass fraction. The experimental results showed that the metal oxides could significantly catalyze the pyrolysis of HTPB-based fuels and enhance the fuel regression rate, and the catalytic effect was mainly concentrated in the middle and late stages of the thermal decomposition process of polybutadiene components. Among the four transition metal oxides, CuO and MnO2 showed better catalytic effects on the combustion performance of HTPB-based fuels in the high oxygen mass flux region, while NiO showed better catalytic effects in the low oxygen mass flux region. The present study compares the regression rate of fuel grains modified with different transition metal oxides, which provides a basis for the selection of future catalysts, verifies the catalytic effect of the transition metal oxides on the combustion of HTPB-based fuels and further analyzes the combustion reaction mechanism of the fuels.

Experimental Investigation of a H2O2 Hybrid Rocket with Different Swirl Injections and Fuels

Hybrid rockets have very interesting characteristics like simplicity, reliability, safety, thrust modulation, environmental friendliness and lower costs, which make them very attractive for several applications like sounding rockets, small launch vehicles, upper stages, hypersonic test-beds and planetary landers. In recent years, advancements have been made to increase hybrid motor performance, and two of the most promising solutions are vortex injection and paraffin-based fuels. Moreover, both technologies can be also used to tailor the fuel regression rate, in the first case varying the swirl intensity, and in the second case with the amount and type of additives. In this way, it is possible not only to design high-performing hybrid motors, but also to adjust their grain and chamber geometries to different mission requirements, particularly regarding thrust and burning time. In this paper, the knowledge about these two technical solutions and their coupling is extended. Three sets of experimental campaigns were performed in the frame of the Italian Space Agency-sponsored PHAEDRA program. The first one investigated a reference paraffin fuel with axial and standard vortex injection. The second campaign tested vortex injection with low values of swirl numbers down to 0.5 with a conventional plastic fuel, namely polyethylene. Finally, the last campaign tested another, lower regressing, paraffin-based fuel with the same low swirl numbers as the second campaign.

Transient numerical investigation on thermochemical erosion of C/C nozzles in hybrid rocket motors

Nozzle erosion is a vital important issue that impacts the performance of hybrid rocket motors. Serious nozzle erosion may significantly decrease the combustion chamber pressure and thrust, which increases the difficulty in designing flight control systems. This paper aims to reveal erosion mechanism systematically. In this paper, transient numerical simulations of thermochemical erosion in hybrid rocket motors are conducted, and combustion flow and thermochemical erosion are coupled calculated. The numerical computation of combustion flow is based on the chemical reactions of propellants and regression rate model, and that of thermochemical erosion is based on the surface reactions between oxidizing species and carbon. The movement of burning surface and nozzle inner surface is simulated through dynamic mesh method. The hybrid rocket motor adopts 90% hydrogen peroxide and hydroxyl-terminated polybutadiene. Distributions of flow field parameters and fuel regression rate are given. The spatial developing process of nozzle surface is presented, and it is found that the roughness of nozzle profile increases with time. The nozzle wall temperature and wall pressure decline with time. Erosion by different species is calculated. OH and H2O make a major contribution to the nozzle thermochemical erosion, while nozzle erosion contributed by CO2 and O2 are quite low. Time-varying characteristics of the erosion rate are unveiled. At the first 1.5 s, the total erosion rate remains almost constant, and then it reduces over time.

Convolutional neural networks for image analysis of high-speed videos from two slab burners

High-speed video recordings of slab burner experiments were analyzed using a machine learning approach with convolutional neural networks in order to compute the regression rate of hybrid rocket fuels over time. Combustion tests of paraffin-based fuel grains performed in two different hybrid rocket slab burners were recorded with high-speed video cameras and the resulting image data are analyzed in order to determine the height of the fuel in each frame. To this end, a deep neural network with U-net architecture is trained in a supervised fashion to segment the shape of the fuel slab. It is demonstrated that this approach is more capable to segment combustion images in unsteady flow conditions than classical computer vision methods based on thresholding or edge detection. Furthermore, methods in the area of uncertainty quantification of neural networks are applied to estimate the errors in the neural network prediction to new previously unseen data. Finally, the regression rate of the fuel is computed as the rate of change of this height. This method enables automatic analysis of a large amount of video data, taking full advantage of the optical access capabilities of slab burners. Additionally, the method delivers not only the time and space average values of the fuel regression rate, but also quantifies its variation over time and over the length of the slab, providing deeper insights into the combustion mechanics of hybrid rockets.

Demonstration of dual-thrust capability in hybrid rockets using multi-layered tubular fuel grains

This study demonstrates the thrust modulation capabilities of a hybrid rocket motor employing a Multi-Layered Tubular (MLT) fuel grain. The MLT configuration involves arranging the fuel grains with distinct regression rates as layers. As combustion progresses, the regression rate changes based on the burning of each fuel layer, leading to variable thrust while maintaining a constant oxidizer flow rate. Variable-thrust fuel grains are suitable for diverse mission types, including employment in sounding rockets and cruise missiles, particularly those designed for anti-ship operations and missions wherein a boost-sustain thrust profile is required. The MLT fuel grains were designed for a boost-sustain phase thrust profile generally observed in missiles. Wax was used as a booster fuel, and wax with 20%EVA was used as a sustainer fuel. Two MLT configurations with different durations for the boost phase were demonstrated. During the tests, the boost-sustain phase was achieved successfully. However, a transition phase was observed while shifting from the boost to the sustain phase. The delay of the transition phase was observed to increase when the duration of the boost phase increased. The combined effect of axial variation of fuel regression rate and local mass flux is the reason for the transition phase. The Thrust Turn-Down Ratio (TDR) for Multi-Layered Tubular (MLT) fuel grains was calculated. At a web thickness (for booster fuel) of 4 mm, the TDR was approximately 1.23:1, and at a 5.5 mm web thickness, it was 1.28:1. Further, 20%Mg was added to the wax to increase the regression rate of booster fuel. The Wax/20%Mg fuel showed 41% and 14% improvement in regression rate and thrust, respectively. The TDR was improved marginally compared to pure wax-based MLT grain.

Supersonic Combustion of Solid Fuels

Supersonic combustion of solid fuels is investigated experimentally using a rectangular-cross-section combustor in the context of understanding ignition characteristics, studying fuel regression, and determining operating conditions. Fuel grains consisted of 3D printed polymethyl-methacrylate of varying geometry. Specifically, the cavity flameholder dimensions are systematically studied to develop a flammability map. Initial examinations reveal that a longer and larger cross-sectional area of the flameholding zone in the fuel grain creates the most optimal conditions for ignition and sustained flameholding. The longer and larger flameholding zone also creates conditions for faster time-averaged regression rates. The ignition characteristics and fuel regression are also examined by varying inlet temperatures of the air, which showed that a higher inlet temperature is conducive to sustained ignition, as well as higher fuel regression rates. This work extends the available literature on supersonic combustion of solid fuels to lower temperatures than has previously been reported.

Pyrolysis–gas chromatography of hybrid rocket fuel comprising low-melting-point thermoplastics

Solid fuels comprising low-melting-point thermoplastics (LTs) have been developed as hybrid rocket fuels. However, it is necessary to improve the regression rate of such fuels for practical application. In this study, the pyrolysis mechanism of an LT fuel in the absence of oxygen was investigated and the combustion-inhibition species among the gaseous pyrolysis products were identified. Pyrolysis–gas chromatography was used to analyze the hydrocarbon compounds produced from the pyrolysis of the LT fuel and its constituents. Detailed chemical reaction simulations were performed to dissect the pyrolysis mechanism of paraffin oil, the principal constituent of the LT fuel. The results revealed that the pyrolysis and evaporation of the fuel components yield aromatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs), which reduces fuel combustion. Notably, the C2H4 generated during paraffin pyrolysis considerably amplified the formation of aromatic hydrocarbons and PAHs, further inhibiting combustion. C2H4 was also identified as one of the potential chemical species that inhibit combustion. The C2H4 ratio in the fuel pyrolysis gas can be considered as an indicator for evaluating fuel compositions that enhance the fuel regression rate.

Solid-Fuel Ramjet Regression Rate Measurements Using X-Ray Radiography and Ultrasonic Transducers

The instantaneous fuel regression rate within a solid-fuel ramjet combustor was characterized using X-ray radiography and ultrasonic transducer measurements. Experiments were performed with cylindrical center-perforated hydroxyl-terminated polybutadiene fuel grains at three mass fluxes () with consistent inlet total temperatures and chamber pressures. Ultrasonic transducer measurements demonstrated changes of web thickness ranging from 7.50 to 9.85 mm and regression rate measurements ranging from 1.35 to . The local maxima of change in the web thickness due to flow reattachment and erosive burning were consistently measured with the ultrasonic transducers. Changes in the port radius on the order of 8–9 mm and regression rates of approximately were deduced from the X-ray radiography images. The structure of the flow reattachment region was evident in measurements from the X-ray radiography images captured near the combustor entrance, whereas images captured at the midlength of the combustor exhibited more uniform fuel regression profiles. Ultrasonic measurements of change in the web thickness were consistently greater in magnitude relative to X-ray radiography measurements. X-ray radiography imaging allowed for the more accurate measurement of fuel regression with the greatest axial spatial resolution, whereas ultrasonic transducer measurements yielded the greatest radial spatial resolution. The change in web thickness calculated with weight-based techniques yielded smaller-magnitude measurements of change in the web thickness relative to X-ray radiography. The regression rate was largely invariant with the mass flux within the investigated operating regime.

Experimental Investigation of a Swirling-Oxidizer-Flow-Type Hybrid Rocket Engine Using Low-Melting-Point Thermoplastic Fuel and Oxygen

Hybrid rockets are safe and inexpensive; however, boundary-layer combustion poses a problem in achieving a fuel regression rate equivalent to that of solid propellants. The fundamental combustion conditions, such as the fuel regression rate of LT421, a paraffin-based low-melting-point thermoplastic fuel, were investigated using a swirling-flow combustion method. Firing tests were conducted using the oxygen mass flow rate and burn time parameters. The LT fuel exhibited an ignition delay compared to polypropylene, and the pressure increased slowly relative to the thrust. The combustion pressure increased or remained constant with time, suggesting that the fuel regression rate was more dependent on the oxygen mass flow rate than the oxidizer mass flux. The shear force generated in the grain owing to the swirling flow caused fuel-grain separation when the oxygen mass flow rate exceeded 100 g/s. Fuel-grain separation was prevented by modifying the case geometry. The maximum fuel regression rate obtained in the tests was 4.88 mm/s at an oxygen mass flow rate of 190 g/s and mass flux of 72.4 kg/(m2s), which was four times higher than that of polypropylene at the same oxidizer mass flux. The fuel regression rate correlation was obtained using the oxygen mass-flow-rate-based parameter, although further modification was necessary to apply this correlation when the burning time was varied.

Combustion studies of MMA/[formula omitted] for a hybrid rocket motor

Poly(methyl methacrylate) (PMMA) is the synthetic polymer of methyl methacrylate (MMA), which is used in a multitude of everyday applications, can also be used as a solid fuel in hybrid rockets. When used as a fuel in a combustion chamber, PMMA undergoes thermal decomposition and phase-change (solid-to-gas), where gaseous MMA (C5H8O2) is the primary product. The gaseous MMA then undergoes combustion with an oxidizer. Experimental studies of this combustion chamber have been performed in literature, and this study helps produce high-fidelity simulations, which can match experimental observations while giving access to more data in the combustion chamber. Simulations of turbulent diffusion flames are performed with gaseous MMA introduced through the combustion chamber walls. Two different diffusion models are used alongside a finite-rate chemistry model to observe the effects of differential diffusion. The rate of inflow of MMA is controlled by the temperature field in the combustion chamber, and the results from the 3D simulation are comparable to 1D counterflow diffusion flame simulations. Simulations are also performed with a tabulated chemistry model developed to improve the computational efficiency and with two different internal diameters to analyze the geometric effects. If one wishes to capture the flow field profiles and fuel regression rate, chemistry effects need to be included. If one wishes to capture the internal chemistry profiles of the combustion products, differential diffusion effects are important. The fuel regression rate and the radial chemistry profiles from the simulations are compared with the experimental results and show good agreement.

Numerical analysis on combustion characteristics of hybrid rocket motor with star-tube segmented grain

A method of star-tube combined segmented grain is proposed to improve the combustion performance of hybrid rocket motor. The star-tube combined segmented grain consists of a single-port star part and a single-port tube part. A mid-chamber forms between the fore-grain and the aft-grain for better mixing effect. The single-port feature gives hybrid rocket motor several advantages, such as simple structure, high reliability, and variable combinations. This paper is mainly aimed at studying the combustion characteristics of hybrid rocket motor with star-tube segmented grain through three-dimensional steady simulations. Combustion performance of the motors with different segmented grain combinations, including fore-tube/aft-tube, fore-tube/aft-star, fore-star/aft-star and fore-star/aft-tube, is contrastively analyzed. The motor in this paper adopts polyethylene and 90% hydrogen peroxide as the propellants. Simulations reveal that segmented grain with different-type grain combinations could greatly change the flow field in the second half of the combustion chamber. Transformation of the flow field is beneficial to the mixing between the fuel and the oxidizer, and it could increase the fuel regression rate and the combustion efficiency. The turbulence effect of tube aft-grain is better than that of star aft-grain. Among the four segmented grain combinations, the combination of star fore-grain and tube aft-grain is the preferred method with optimal overall performance. This grain configuration could increase the regression rate of tube aft-grain to surpass that of star aft-grain in other combinations. Besides, hybrid rocket motor with this grain configuration achieves the highest combustion efficiency.

Numerical and experimental analysis of fuel regression rate in a lab-scale hybrid rocket engine with swirl injection

In this work the regression rate performance and flow physics of a lab-scale hybrid rocket engine burning gaseous oxygen and paraffin-based fuels are experimentally and numerically investigated. Regression rates are obtained by thickness-over-time averaging procedures and through a non-intrusive optical method enabling fuel grain port diameter tracking. A numerical rebuilding of the experimental data is performed with axisymmetric Reynolds-averaged Navier-Stokes simulations, using sub-models accounting for the effects of turbulence, chemistry, radiation, and fluid-surface interaction. Simulations are performed with different computational setups, also considering the fuel grain shape variation over time, obtaining a fairly good agreement between the numerical and experimental data. A parametric analysis is also performed to assess the variation of the fuel regression rate with swirl intensity.

Experimental Firing Test Campaign and Nozzle Heat Transfer Reconstruction in a 200 N Hybrid Rocket Engine with Different Paraffin-Based Fuel Grain Lengths

Firing test campaigns were carried out on a 200 N thrust-class hybrid rocket engine, using gaseous oxygen as an oxidizer and a paraffin-wax-based fuel. Different fuel grain lengths were adopted to extend the fuel characterization under different operating conditions, and to evaluate rocket performances and internal ballistics in the different configurations. In addition to data collected under a 220 mm propellant grain length, two further test campaigns were carried out considering 130 mm and 70 mm grain lengths. Two different injector types were adopted in the 130 mm configuration; in particular, a showerhead injection system was used with the aim to contain high-amplitude pressure oscillations observed during some firing tests in this engine configuration. Parameters such as the chamber pressure and temperature inside the graphite nozzle, space-averaged fuel regression rate and nozzle throat diameter were measured. The results allowed for the investigation of different issues related to hybrid rockets (e.g., fuel regression rate, engine performance, nozzle ablation under different conditions). The focus was mainly directed to the nozzle heat transfer, through the reconstruction of the convective heat transfer coefficient for different tests in the 70 mm grain length engine configuration. The reconstruction took advantage of the experimental data provided by the nozzle embedded thermocouple. Then, the experimental convective heat transfer coefficient was used to validate the results from some empirical correlations. The results showed significant differences between the experimental convective heat transfer coefficients when considering tests with different oxidizer mass flow rates. Furthermore, the predictions from the empirical correlations proved to be more reliable only in cases characterized by oxidizer-rich conditions.

Experimental Research on Reconstruction Techniques for Instantaneous Regression Rate of Hybrid Rocket Motor with Single-Port Wagon Wheel Fuel Grain

This study investigated reconstruction techniques for building the instantaneous fuel regression rate of the hybrid rocket motor (HRM). Specifically, an experiment in a laboratory 500 N-class hybrid rocket motor with single-port wagon wheel fuel grain, operated with hydrogen peroxide (HP) and hydroxyl-terminated polybutadiene (HTPB) based fuel (including Al), was carried out. A piece of post-processing software was developed to reconstruct the instantaneous regression rate and other performance parameters of the HRM during the firing test. The results produced by the reconstruction techniques are in good agreement with experimental data obtained by traditional methods, with a maximum error of less than 5.75%. Moreover, compared with the traditional endpoint method, the reconstruction method had a significant advantage, which could ascertain the sensitivity of the regression rate to changes in the oxidizer mass flux and fit the formula of regression rate in a single firing test. Additionally, digital image processing techniques were employed to determine the axial distribution of the fuel regression rate after the test using computed tomography (CT) scanning. This served to verify the accuracy of the instantaneous reconstruction calculation. The error in the average regression rate between CT scanning and the reconstruction calculation was 1.91%, proving that the CT scanning and pixel statistic method of the calculating regression rate was practical for characterizing the axial distribution of the average regression rate during the firing test. In summary, the main objective of this study was to reconstruct the transient parameters of hybrid rocket motor with single-port wagon wheel fuel grain using reconstruction techniques, and to fit the formula of the regression rate through a single-firing test. Furthermore, this paper proposes a modified reconstruction method that is essential for investigating fuel regression rate during the firing test of HRMs.

Numerical analysis of fuel regression rate and flow field in solid fuel ramjet with the gas generator

In this paper, to improve the combustion characteristics and working performance of the solid fuel ramjet, a solid fuel ramjet with a gas generator is proposed. Based on k − ω SST and Eddy-Dissipation equations, the turbulent combustion model is established, and the internal flow field of the ramjet, as well as the regression rate, and species, were numerically analyzed. The results show that the temperature of the ramjet and the regression rate with a gas generator is increased. When the airflow is 0.4kg/s, the increase of the gas generator flow will lead to a more obvious regression rate increase, and the maximum value will increase by 33%. When the airflow is 0.6kg/s, the regression rate with the gas generator is evenly distributed along the axis. The flame with a gas generator makes the head burn more completely, the combustion chamber temperature increases, and the average regression rate of solid fuel increases by 14%.

Investigation of dynamic mixing combustion characteristics in variable thrust hybrid rocket motors

The dynamic mixing combustion characteristics in variable thrust hybrid rocket motors (HRMs) have been investigated by using a newly developed two-dimensional transient numerical model. This model takes into account the heat transfer process in the solid fuel grain coupled with dynamic combustion flow in HRMs. Fire experiments were conducted to validate the developed model by using an optical-access slab burner and a lab-scaled HRM. It shows that the model developed in the present work can predict accurately the regression behavior of fuel grains in HRMs. Based on this model, simulations of two variable thrust processes with different thrust ratio were performed. The results show that the recirculation zones located at pre- and post-combustion chamber directly affects the inhomogeneity of the temperature distribution of the inner surface of the fuel grain, leading to a fuel regression rate difference along axial direction. In thrust variation process, the fluctuation duration of the fuel regression rate is longer than the regulation time of oxidizer flow. The fluctuation range of regression rate is influenced by the amplitude and proportion in oxidizer flow regulation. In addition, a decrease in the characteristic velocity and combustion efficiency (from 97.1% to 72.63% and 70.64%, respectively) was observed during the thrust variation process. A slight thrust loss was observed at all stages of the variable thrust process and reaches to maximum value at an oxidizer flow rate of 20 g/s for the lab-scaled HRM studied in the present work.

COMBINED DATA AND DEEP LEARNING MODEL UNCERTAINTIES: AN APPLICATION TO THE MEASUREMENT OF SOLID FUEL REGRESSION RATE

In complex physical process characterization, such as the measurement of the regression rate for solid hybrid rocket fuels, where both the observation data and the model used have uncertainties originating from multiple sources, combining these in a systematic way for quantities of interest (QoI) remains a challenge. In this paper, we present a forward propagation uncertainty quantification (UQ) process to produce a probabilistic distribution for the observed regression rate r. We characterized two input data uncertainty sources from the experiment (the distortion from the camera <i>U</i><sub>c</sub> and the non-zero-angle fuel placement <i>U</i><sub>Y</sub>), the prediction and model form uncertainty from the deep neural network (<i>U</i><sub>m</sub>), as well as the variability from the manually segmented images used for training it (<i>U</i><sub>s</sub>). We conducted seven case studies on combinations of these uncertainty sources with the model form uncertainty. The main contribution of this paper is the investigation and inclusion of the experimental image data uncertainties involved, and how to include them in a workflow when the QoI is the result of multiple sequential processes.

High entropy alloy as metal additive for hybrid rocket propellant

A typical solid propellant used in rocket propulsion systems is made from polymeric fuel, crystalline liquid binder and additives. In comparison to conventional propulsion systems, hybrid propulsion is more safe, reliable and environmentally friendly. However, the hybrid systems have some drawbacks, including low fuel regression rates and low combustion efficiency. As a result, several approaches have been developed to increase the rate of solid fuel regression rate including the introduction of metal additives to the system. Nowadays, high entropy alloys (HEA) are among the most advanced materials for high-performance applications. This alloy has a potential to replace the existing metal additives in hybrid propulsion systems. The present work proposes a new composition based on Paraffin wax fuel, loaded with high entropy alloy as a metal additive for hybrid propulsion systems using the following ratio of 80:20. Therefore, this research explores the efficacy of high entropy alloys as additives for hybrid propulsion systems. Characterizations and thermal analysis of solid fuel using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis are carried out to determine the structure, thermal decomposition and energy characteristics of the solid fuel with the HEA as additive. XRD result shows that HEA in a form of solid solutions produces BCC and FCC structures. Thermal analysis of paraffin wax with the addition of HEA gives the maximum value of 136.34 J/g for the total latent heat of the mixture. It is concluded that HEA increases the energy released from the fuel by 86.92 % compared to pure paraffin wax fuel. The mixture of paraffin and HEA fuel has a prospect to be used as future rocket fuel.