Heat Protection Research Articles

Synergistic reinforcement and multiscaled design of lightweight heat protection and insulation integrated composite with outstanding high-temperature resistance up to 2500 °C

Developing lightweight and efficient ablation-resistant materials with thermal insulation and conformability over 2500 °C is extremely important for the thermal protection of hypervelocity aerospace vehicles, but significant challenges remain. Herein, a unique lightweight heat protection and insulation integrated composite (QCF/SPA) is developed by a hierarchical construction strategy, integrating macro-scale quartz/carbon hybrid fiber preform, micro-scale silicone aerogel, and nanoscale phenolic aerogel. The QCF/SPA with the macro-micro-nano multiscale structure has the advantages of low-density nature (0.33 ± 0.02 g/cm3), superior insulation (0.050–0.063 W/(m·K)), excellent thermal stability, and mechanical strength. More importantly, the QCF/SPA has outstanding ablation resistance and thermal insulation based on the efficient dual silicon & dual carbon multiple synergistic mechanism originally proposed in this work. The line ablation rate and mass ablation rate reached 0.058 mm/s and 0.014 g/s under the 3.62 MW/m2 oxyacetylene assessment. The as-fabricated QCF/SPA with these combined properties is ideal for thermal protection systems of hypervelocity spacecraft, space re-entry vehicles, rocket propulsion devices, and missile launchers.

Obtention of Sacha Inchi (Plukenetia volubilis Linneo) Seed Oil Microcapsules as a Strategy for the Valorization of Amazonian Fruits: Physicochemical, Morphological, and Controlled Release Characterization.

Sacha inchi seed oil (SIO) is a promising ingredient for the development of functional foods due to its large amount of high-value compounds; however, it is prone to oxidation. This work aimed to obtain SIO microcapsules using conventional and ultrasound probe homogenization and using spray- and freeze-drying technologies as effective approaches to improve the long-term stability of functional compounds. The application of ultrasound probe homogenization improved the rheological and emulsifying properties and decreased the droplet size and interfacial tension of emulsions. The microcapsules obtained by both drying technologies had low moisture (1.64-1.76) and water activity (0.03-0.11) values. Spray-dried microcapsules showed higher encapsulation efficiency (69.90-70.18%) compared to freeze-dried ones (60.02-60.16%). Thermogravimetric analysis indicated that heat protection was assured, enhancing the shelf-life. Results suggest that both drying technologies are considered effective tools to produce stable microcapsules. However, spray-drying technology is positioned as a more economical alternative to freeze-drying.

Halloysite/phenol-formaldehyde nanocomposites with enhanced mechanical properties and lowered fire hazard

Development of highly filled nanocomposites with simultaneous enhanced properties in mechanical properties, anti-ablation and inflaming retarding is still a challenge. In this study, halloysite/ phenol-formaldehyde (Hal/PF) composites with different filling rate (10, 20, 30, 40 and 50%, g/g, Hal/PF) were prepared. Hal can achieve good dispersibility even at highest filling rate, in which the tensile strength increases by 39%. The ablation performance tests indicate that the linear ablation rate decreases by 23% as compared to PF resins without the addition of Hal. Moreover, the formation of ceramic-like particles has been confirmed based on the characterizations of XRD, SEM, TEM mapping and Raman spectrometer. Cone calorimetry and vertical combustion tests show that the Hal/PF composites exhibit reduced combustion, retarded fire spread, reduced harmful gas production, lowered fire risk and reduced combustion degree. The as-prepared Hal/PF composites with simultaneous enhanced properties in stretching, impact, anti-ablation and inflaming retarding may provide more room to enrich the family of PF composites and extend their potential application in heat protection field.

Study on the Ablation Mechanism of the First Pulse Insulation Layer in a Double-Pulse Solid Rocket Motor

In this work, numerical simulation and experimental research were carried out on ablation mechanism of the first pulse (I pulse) insulation layer in a double-pulse solid rocket motor (SRM). Firstly, based on the internal thermal environment of the typical double pulse SRM, the internal flow field in combustion chamber of the double-pulse SRM with soft type pulse separation device (PSD) under the second pulse (Ⅱ pulse) working condition was numerically simulated. The results showed that the main reason for the difference of ablation in I pulse insulation layer was the difference of gas phase velocity. Secondly, based on the simulation analysis results, the experimental system for ablation of insulation layer was developed, and the ablation performance experiments under two gas phase velocities were carried out. It was found that a brittle carbonized layer had been formed on the surface of the insulation layer after the completion of I pulse work. In addition, at the beginning of Ⅱ pulse work, the suddenly generated gas flow made a denudation effect on the carbonized layer, which consumed a part of the carbonized layer. After the carbonized layer was peeled off, the gas flow continued to ablate the matrix of the insulation layer. Finally, the simulation analysis of the ablation process of the insulation layer under two gas phase velocities was carried out. The results showed that the velocity of the fuel gas is the main factor affecting the ablation rate of the insulation layer, which was consistent with the experimental results. It is proven that the model can be used to estimate the ablation amount of insulation of solid rocket motor. The conclusion can provide a significant reference for the internal heat protection design of the double-pulse SRM.

Overheating of residential buildings in the severe cold and cold regions of China: The gap between building policy and performance

Given the forecasts of global warming and heatwaves, concern is growing about the exacerbation of overheating in dwellings in severe cold and cold regions of China. This concern, however, has been neglected by Chinese national building codes and standards. The focus in these regions has been to preserve heat during winter, lacking in definite measures prescribed for heat protection during summer. Although many studies have examined the situations in Europe, limited effort has been devoted to investigating overheating in China. The aim of this research is to use validated simulation results and empirical data to reveal overheating risk in these regions of China and identify deficiencies in local standards. The indoor temperature of residential buildings in four representative cities (Yichun, Harbin, Shenyang and Dalian) was measured from May to September 2021. To extend the observation period and enhance the reliability of the results, this study carried out building performance simulations using typical weather data over 15 years (2004–2018). Having the models validated, the results revealed the severity of overheating phenomenon. During the summertime (May to September), overheating were recorded for 6, 191, 483 and 578 h out of total 3672 h (accounted for 0.4%, 12.4%, 31.6% and 37.6%) in the south-facing bedrooms of Yichun, Harbin, Shenyang and Dalian respectively. It is therefore suggested that the design standards should consider a trade-off between thermal retention in winter and overheating in summer. The findings provide useful information and guidance for policymakers contemplating low-carbon building schemes and regulations on thermal comfort.

Realistic representation of city street-level human thermal stress via a new urban climate-human coupling system

Urban overheating aggravated by climate change and rapid urbanization poses a severe threat to thermal health of urban residents. To more realistically represent street-level heat stress, we propose a new urban climate-human coupling system by integrating an advanced urban canopy model (UCM) with a new human-environment adaptive thermal stress (HEATS) module. The coupled UCM-HEATS system features a state-of-the-art solution to complicated human-street radiative exchanges and incorporates dynamic human thermoregulatory responses to microclimatic changes. The UCM-HEATS system was evaluated in a typical hot and humid city, Hong Kong, and then applied to investigate street-level thermal stress in various urban settings and under different personal conditions. By explicitly resolving shading effects of buildings and trees on human radiation budgets, our study emphasizes the marked effectiveness of active shade management using green and gray infrastructure on daytime heat mitigation, proposing a “right shade, right place, right time” paradigm for regulating important street canyon geometries (building height, road width, and tree crown width) and orientations. Additionally, human evaporative heat dissipation can be hindered by urban moisture islands and wind impediments; thus, a detailed urban ventilation strategy is suggested considering different temperature-humidity combinations. For personal heat protection, we identified an evident cooling effect of high-albedo clothing and a thermal-comfort-optimal walking speed. Special attention is paid to heat-vulnerable groups, especially older people who suffer from notably higher heat risks during pandemics with facemask-induced heat burden. Bridging urban climate and human ergonomics, this study aims to advance human-centric urban design toward future smart, resilient, and inclusive cities.

An innovative thermal protective clothing system for firefighters

Nowadays, despite the evolution of personal protective equipment (PPE), the number of firefighters injured and burned during fire extinguishing operations is still very high, leading in some cases to loss of life. Therefore, the research and development of new solutions to minimize firefighters’ heat load and skin burns, with consecutive improvements of commercial firefighters’ suits, is of extreme importance. The integration of phase change materials (PCMs) in a protective clothing system has been used to significantly reduce the incoming heat flux from the fire environment. This study consists in the development of a protective clothing system composed by a vest, specially designed to protect the torso (back, chest and abdomen) with a layer of PCM pouches, to be worn over a fire-resistant jacket – selection and design based on numerical models’ predictions. Therefore, several mockups were made, varying the number of PCM pouches and their distribution in the vest, allowing the creation of air ducts to increase the breathability of the vest. The most promising solutions are being evaluated in a real controlled environment, at a Portuguese National School of Firefighters (ENB) simulation site, using a fire manikin and thermocouples to monitor vest temperature during heat and flame exposure, and consequently to verify PCMs influence in heat protection. Results regarding the development of a PCM vest will be presented, focusing on the integration of PCM pouches and the thermal performance of the most promising solutions.

Optimization of anti-bending deformation of aerogel sandwich thermal protection structure

The failure of the thermal protection structure is very important to the safety of the aircraft structure. In order to accurately predict the flexural behavior of the aerogel sandwich thermal protection structure, first of all, for the sandwich structure in the form of statically indeterminate beam with variable cross-section, the beam theory considering the transverse shear deformation of the core layer was deduced. Secondly, by comparing the deflections, the forms of deflection curve and the maximum strains of the upper panel, the accuracy of the theoretical prediction was analyzed. Then, according to the requirements of heat protection and integrity of the thermal protection structure, the optimization analyses of the parameters of the core layer, such as the thickness, the density and the elastic modulus, were carried out. The results showed that the beam theory considering the transverse shear deformation of the core layer had better prediction accuracy. The maximum deflection error was the smallest, which was -17%, and the form of the deflection curve was the most reasonable. Within the range of the physical parameters of the core layer studied, the theoretical basis and guiding direction were given for the regulation of the performance of the aerogel core layer.

Effects of fuel conversion ratio on cooling and drag reduction performance for supersonic film using gaseous hydrocarbon fuel

Film cooling especially combined with regenerative cooling is an effective solution to meet the heat protection and the drag reduction demands for hydrocarbon-fueled scramjet engines. Typically, fuel is the only available coolant to organize the active cooling for hypersonic vehicles, and the coolant used in the film cooling is extracted from the regenerative cooling channels; however, the fuel pre-cracking in the regenerative cooling process must be considered as it can change the initial composition and energy level of the coolant in the film cooling. Numerical simulations based on the RANS method are conducted to evaluate the effects of film pre-cracking on its cooling and drag reduction performance, by changing the fuel conversion ratio from 0 to 40 %. Results show that the influence of film inlet cracking on its drag reduction performance is limited, and the relative change of the wall friction under different conversion ratios is less than 5 %. However, the film inlet cracking has a notable negative influence on its thermal protection performance. Specifically, for every 10 % increase in the film conversion ratio, the average adiabatic wall temperature will rise by about 20 K. Further analysis reveals that although the total amount of the fuel chemical heat sink is comparable to its physical heat sink, only around 25 % of the film chemical heat sink can be effectively used to enhance the fuel film cooling performance. The loss of the effective chemical heat sink during the pre-cracking process is the main reason for the decrease of film cooling performance as the film inlet conversion ratio increases.

Heat transfer and protection of high-temperature reheater of a 660 MW circulating fluidized bed boiler after black out

• Heat transfer model of buried tube in external heat exchanger was established. • Safety of 660 MW circulating fluidized bed reheater was evaluated when black out. • Correlation between minimum working fluid flow and some key factors was analyzed. With the increase of boiler capacity and steam parameters, compared with other circulating fluidized bed (CFB) boiler, the high-temperature heating exchangers in a 660 MW CFB boiler may face severe potential safety problems after black out, especially the reheater in the external heat exchanger (EHE). In this study, a numerical simulation was conducted to predict the heating transfer process of an EHE after black out in a 660 MW ultra-supercritical CFB boiler. The tube temperature of the reheater inside the EHE was also estimated. It was found that metal tubes of the reheater are probably overtemperature. Therefore, to protect the metal tube from the overtemperature damaged, the additional cold water has to be given inside the reheater. The tube temperature rises first and then falls, and the highest temperature will be reached within tens to hundreds of seconds. The minimum flow rate of cold water to ensure the safety of the pipe was also estimated under different conditions. Some key parameters including the bed temperature of the EHE, thermal diffusivity of the bed materials and thermal deviation of the reheater were also analyzed, which are of great significance to the safety of the EHE and the economics of the emergency water system.

EXPERIMENTAL ANALYSIS OF THE EFFECT ADDITION HEAT COVER IN DISTILLATION REACTOR

Distillation is the process of separating two or more components of a liquid based on their boiling points in which the material to be evaporated is contained. Distillation is simply done by heating/evaporating the liquid and then changing the vapor phase to liquid with the help of a condenser. Research on the distillation column or reactor has been carried out to improve the distillation system but is still discussing the reactions that occur due to heating and the final product of the distillation process. An analysis based on the second law of thermodynamics is developed, known as exergy analysis to obtain information about the thermodynamic efficiency and locations that have low energy efficiency so that energy savings can be targeted. The distillation reactor as one of the vital tools at the separation stage is very important to note is the manufacture of the reactor. To reduce heat loss that occurs by adding a heat protective layer (heat cover) on the distillation reactor. The heat protection materials used are burlap sacks and glass wool to be implemented for rural communities and also become prototypes of appropriate technology application tools. The use of a 3 cm jute alloy on the inside and 3 cm glass wool on the outside gave the highest heat transfer value of 7864.21 watts. The increase was 43% of those who only used burlap. An increase of 37% over those using only glass wool. A 3% improvement over an alloy of 3 cm glass wool inside and 3 cm burlap on the outside.

Passive Cooling System to Provide Thermal Comfort

Abstract: In a country like India, where temperatures may reach 40 degrees Celsius, everyone wants relief from the sweltering heat, but only a few can afford it. As a result, passive cooling is a low or no energy approach that relies on heat gain management and heat dispersion to offer thermal comfort. Heat Protection, Heat Modulation, and Heat Dissipation are the three basic types of passive cooling systems. The combined effect of approaches from each category on a prototype room is examined in this research, which includes shading and green roofs for heat protection, thermal mass (PCM) for heat modulation, and cross ventilation for heat dissipation. Thermal mass is a term that describes a substance's ability to store heat. The three primary phases of a Thermal Energy Storage (TES) system are thermal charging, thermal storage, and thermal discharging. Phase Change Materials or PCM are latent heat storage materials. The roof is one of the most exposed parts of a house to the sun, accounting for over half of the heat gain in a single-story home. As a result, heat protection might be a viable option for lowering heat gain via the roof. A green roof, or a roof with vegetation, is one such system that operates on the principle of evapotranspiration, which is the combined action of soil evaporation and plant transpiration. Another effective method of heat shielding that is used in everyday life is shading. Shading is a basic technique for blocking sunlight before it enters a structure by using structural components such as overhangs, light shelves, horizontal louvres, or blind systems. Cross ventilation is a natural cooling method that uses wind to force cold air into a structure through an opening while driving warm air out. Natural ventilation of this sort is low-cost and ensures that a structure is suitably cooled. There are many such different passive cooling techniques used in different regions of the world in the form of individual as well as hybrid system. This project focuses mainly on Hybrid Systems. Thus, the objective of this project is to integrate PCM and other secondary passive cooling techniques for creating a hybrid passive cooling system to provide thermal comfort.

ДОСЛІДЖЕННЯ МЕХАНІЗМУ ВОГНЕЗАХИСТУ ТКАНИНИ ІНТУМЕСЦЕНТНИМ ПОКРИТТЯМ

Describing the behavior of fire retardants and coatings, including swelling, at the time of formation of the insulating structure is a separate and complex task. In general, it covers both stages of the heat protection process: as a rule, the decomposition of flame retardants under the action of temperature with heat absorption and the release of non-combustible gases, and then - swelling of the coating formed by fire protection. Therefore, it is necessary to study the conditions for the formation of a barrier to thermal conductivity and the establishment of a fire protection mechanism from layer to layer of coke. In this regard, a study of the process of fire protection during the operation of the fire protection coating. According to the data obtained, it is found that the formation of volatile products under the action of high temperature on the coating takes place with the formation of non-combustible substances. It has been experimentally established that under the action of heat flow on fire-retardant samples there is an intensive release of inert gases and a reduction of combustibles in reverse order. This proves the effectiveness of fire protection. During the tests it was found that the intensity of the formation of the swollen layer of coke moves in the direction of elevated temperature. The results of determining the swelling capacity of the coating for the intumescent system showed that under the action of high-temperature flow the burnout of the material and the loss of coating weight are reduced more than twice due to the formation of high-temperature compounds. The coating under the action of high temperature forms a significant coefficient of swelling, promotes the formation of a heat-insulating layer of coke, preventing burnout of the fabric and the passage of high temperature to the material, which is confirmed by reduced heat of combustion. It was determined that the fire-retardant fabric has almost 1.3 times less heat of combustion and is characterized by thermal decomposition by reducing flammable gases by more than 50% and increasing inert gases by more than 8 times.

Methods of Preliminary Estimation of Total Solar Energy Transmittance (TSET) on a Sun Protected Window with Climatic Chamber and Hot Box Apparatus

Abstract The total solar energy transmittance (TSET, g - value) is a parameter of transparent system, which can significantly affect the heat demand for cooling of buildings in the summer. A wide range of progressive transparent and shading systems have been developed and applied to a large number of buildings. Their energy performance and efficiency can be determined using simulation tools or measurements. The methodology for accurate g - value determination is described in ISO 19467: 2017. The aim of the study was to derive and verify an alternative methodology for estimating the total solar energy transmittance of selected specimens of transparent systems in case when the standardized equipment is not available or the aim is not to know the exact TSET value. Window specimens were tested under laboratory conditions, which were retrofitted with elements that improve their original properties in terms of heat transfer coefficient and protection against overheating. In total, three methodologies were designed and described, based on A) monitoring of heat fluxes through glazing, B) monitoring of temperature rise in the hotbox and simulation, and C) determination of the difference in heat fluxes of an irradiated specimen and in the absence of radiation. A solar simulator and a heated hotbox were used for the measurements according to the needs of the chosen methodology. The results from the different approaches for determining g - values differ only slightly but are informative. The conclusion from all measurements is the fact that the tested specimens representing type of windows applicable in building retrofitting showed high potential in terms of reducing heat gains from the sun.

Low-Density Resin-Based Ablative Heat Protection Materials

The severe aerodynamic heating that occurs when a spacecraft reenters the atmosphere takes place. The material used for thermal protection is an essential part of the system used for thermal protection. A number of chemical and physical transformations take place in the ablation heat-resistant material that is based on resin. This material is an organic polymer. We herein briefly review the status quo of low-density resin-based ablative heat protection materials.

INVESTIGATION OF PRODUCTION TECHNOLOGY BY PRESSING OF PLASTIC MASS PARTS IN OIL MINING EQUIPMENT

Plastic parts in oilfield equipment have high performance and are widely used in the manufacture of various structural parts using simple processing methods. These details are widely used in oil and gas equipment due to their quality of heat and electrical protection in the chemical environment, longevity and low specific gravity. Keywords: plastic parts, pressing, press mold, mold matrix, mold punch.

Superelastic and responsive anisotropic silica nanofiber/polyvinylpyrrolidone/MXene hybrid aerogels for efficient thermal insulation and overheating alarm applications

Although silica aerogels with ultralow thermal conductivity are competitive for thermal insulation, their deficiencies in mechanical properties and single function affect their wide applications. Herein, we demonstrate a “soft fiber-stiff sheet” synergistic strategy for fabricating superelastic and responsive anisotropic silica nanofiber/polyvinylpyrrolidone/MXene hybrid aerogels by electrospinning, calcination, and directional-freezing. The anisotropic hybrid aerogel exhibits satisfactory thermal insulation performances at both high and low temperatures, delivering a low thermal conductivity of 21 mW m−1 K−1. The top surface temperature of the hybrid aerogel maintains at ∼74 °C after its standing on a hot plate of 300 °C. By putting the hybrid aerogel on a cold plate of −30 °C, its surface temperature is only 7.2 °C lower than the ambient temperature. Interestingly, the oxidation of MXene at high temperatures could transform the hybrid aerogel from electrically conductive to insulating, leading to sharp changes in electrical signals to trigger overheating alarm. Furthermore, the hybrid aerogel exhibits high compressibility and fatigue resistance with a high stress retention rate of 97.3% after 100 cycles under the compressive strain of 50%. Such compressive and thermally insulating aerogels are promising thermal management materials for smart alarms, and heat and cold protection of electronic devices.

The Effect of the Season, the Maintenance System and the Addition of Polyunsaturated Fatty Acids on Selected Biological and Physicochemical Features of Rabbit Fur.

Simple SummaryRabbit furs are a valuable material used in the fur industry. Many studies show beneficial effects of omega-3 acids supplementation on the skin and coat of animals. The aim of the study was to show the impact of environmental conditions and dietary supplementation with ethyl esters of linseed oil on the quality of the rabbit hair coat. The experiment was carried out in four stages: laboratory (summer and winter) and outdoor (summer and winter). The experimental rabbits were given an addition of ethyl linseed oil to their feed (during 2 months). To assess biological and physico-mechanical properties of the coat samples and to determine fatty acid profile and histological evaluation, the hair samples were collected three times: before the study, after two months of treatment, and after two months from the end of supplementation. The obtained results show that the environmental conditions have a major impact on the quality of the rabbit coat. The best results of hair heat protection were obtained from animals kept outdoors. Administration of linseed oil ethyl esters had a positive effect on the hair fatty acid profile.The aim of the study was to show the impact of environmental conditions and dietary supplementation with ethyl esters of linseed oil on the quality of the rabbit hair coat. The research was divided into 4 stages: laboratory (summer and winter) and outdoor (summer and winter). In each stage of the research, animals were divided into control and experimental groups. The animals were fed in accordance with the feeding standards of reproductive rabbits during the period of sexual dormancy. The rabbits from the experimental groups during the first two months were given an addition of ethyl linseed oil to the feed. In the experiment, linseed oil was cold-pressed directly in the laboratory. Three samples of hair were collected: before the study, after two months of treatment, and after two months from the end of supplementation. The hair coat biological properties, such as share of individual hair fractions (%), heat transfer index (HTI), hair diameter (μm), as well as physico-mechanical properties such as breaking force (N), breaking stress (kg/cm2) and elongation (%) were performed. Moreover, the histological structure of hair and histological hair evaluation were performed. The fatty acid profile was determined in the hair as well. The obtained results of the content of individual fatty acids were grouped into saturated fatty acids and unsaturated fatty acids. In addition, omega-3 and omega-6 were distinguished from the group of unsaturated acids. The environmental conditions have a major impact on the quality of the rabbit coat. The best results of hair thickness and their heat protection were obtained from animals kept outdoors. The studies did not show an influence of the administered preparation on the quality of the rabbit coat. The hair became thinner, but more flexible and tear-resistant. Administration of linseed oil ethyl esters had significant, beneficial changes in the fatty acid profile in hair and hair sebum were observed. There was a significant increase in omega-3 acids, and a significant decrease in the ratio of omega-6 to omega-3 acids.

Characterization of scents from Juniperus chinensis by headspace in-needle microextraction using graphene oxide-polyaniline nanocomposite coated wire followed by gas chromatography-mass spectrometry

Scents released by trees are the secondary metabolites that play various roles, including indirect plant defense against insects, attraction to pollinators, communication, adaptation to heat resistance, environmental stress, and protection from predators. In this study, the scents of three individual trees designated as Korean natural monuments (pair of Chinese junipers, Chinese juniper, and horizontal Chinese juniper tree) were analyzed using headspace in-needle microextraction (HS-INME) method with graphene oxide-polyaniline (GO-PANI) adsorbent followed by gas chromatography-mass spectrometry (GC/MS). GO-PANI layer was coated on a stainless steel wire using cyclic voltammetry (CV). It was characterized through thermogravimetric analysis (TGA), Fourier transform-infrared spectroscopy (FT-IR), and field emission-scanning electron microscope (FE-SEM). As a result, it was confirmed that the GO-PANI coating was successfully prepared. α-Longipinene, α-cedrene, and cedrol, which are representative scent components of common juniper trees, were selected as target compounds through a preliminary test and used in the optimization processes. Response surface methodology (RSM) with Box Behnken Design (BBD) was applied to optimize the experimental conditions. The developed analytical method was validated by checking the limit of detection (LOD), the limit of quantitation (LOQ), recovery rate, sensitivity, and reproducibility. Significant scientific findings from three Korean natural monuments of Juniperus chinensis were characterized by their major scent components such as α-cedrene, γ-cadinene, thujopsene, and cedrol of pungent-woody base note.

Research on drag reduction and heat prevention performance of spike with the channel concept for hypersonic blunt body

Abstract To answer the difficulties of drag reduction and heat protection for hypersonic vehicles, a new type of a spike with a channel entrance at the head and a lateral outlet was devised. When contrasted to a solid spike, once the channel is added, the lateral exhaust pulls the separated shock wave away from the spike, reducing the strength of the reattached shock wave and dramatically enhancing heat resistance. In this study, the affecting features of the new idea model are investigated. The findings show that the larger the half-angle of channel convergence, the better the model’s overall drag reduction and heat prevention effectiveness. In the research range, the model with a 60° convergence half angle delivers the best overall advantage in terms of drag reduction and heat prevention. The total resistance of the model was reduced by 14.44 %, and the peak heat flux of the blunt-body wall was reduced by 33.84 % compared to the solid spike.