Enhancing solid rocket propellants with nano-additives: a review of thermal and kinetic performance Rahul Kumar, Deepak Sharma, Yarrapragada K. S. S. Rao, Ashish Kumar, M. Dubey, Shri Krishna Mishra, Ashu Yadav Discover Applied Sciences, 2025 This study critically focuses on the recent trends concerning ammonium perchlorate (AP) based solid rocket propellants with nano-additives, focusing on their thermal and kinetic parameters such as activation energy, burning rate, thermal decomposition temperature, and apparent heat of thermal decomposition, providing a brief overview of the overall efficiency of the propellant, and can be used as a baseline for further research. Although AP is one of the most widely used solid rocket propellants, it suffers from low burning rates, thermal sensitivity at high temperatures, catalytic decomposition, sensitivity to shock and friction, and lower combustion efficiency as a whole, including environmental concerns due to its emission of hydrochloric acid on combustion, which not only affects its efficiency but also its marketability as industries related to aerospace and defence focus mainly on high-efficiency propulsion solutions. Nano-additives varying between metallic forms, represented by aluminium, iron oxide (Fe 2 O 3 ), and magnesium, and non-metallic forms based on graphene and carbon nanotubes-focus on enhancing the thermal and kinetic parameters of AP while reducing the toxic fumes released. The key findings from this review include a significant reduction in decomposition temperature and activation energy, along with a general increase in burning rate and heat of decomposition, which yields a much more efficient propellant. Using metal-based (e.g., Fe 2 O 3 ) and carbon-based (e.g., graphene oxide, carbon nanotubes) additives can reduce HCl emissions from AP combustion by 35–60% compared to baseline formulations, lowering exhaust chlorine content from 19 wt% to below 8–12 wt%, meeting environmental acceptability thresholds for aerospace applications.
Experimental analysis of a diesel engine run on non-conventional fuel blend at different preheating temperatures Rahul Kumar, Anil Singh Yadav, Abhishek Sharma, Upendra Rajak, Tikendra Nath Verma, Tabish Alam, Nishant Tiwari, C P Jawahar Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering, 2025 Due to urbanisation, the reuse of scrap tyres in the form of energy has gained attention for the disposal of waste tyres. Among the numerous methods, pyrolysis appears to be possible, appealing and viable for generating products such as pyrolysis oil, which can be combined with petroleum oils and used as a source of energy. In a prior study, a mixture of jatropha methyl ester (JME) and tyre pyrolysis oil (TPO) was used as a diesel engine fuel, and it was discovered that the JMETPO20 (JME80% + TPO20%) blend gave better results among all the test blends but inferior than diesel operation. Also, it was reported that due to higher viscosity of the JMETPO20 blend, engine gave inferior performance than diesel operated engine. In this context, an attempt has been made to utilize the JMETPO20 blend at different preheating temperatures to substitute conventional diesel. The blend was preheated at three different temperatures, that is, 50, 60 and 70°C and experiments were carried out in a single-cylinder diesel engine with a rated output of 4.4 kW. The results of the investigations were analysed and compared with diesel and presented in this study.
Speculative investigation of performance & combustion of waste plastic oil blended with diesel as an alternate fuel in single cylinder diesel engine employing is: 10000 standards Maulik A. Modi, Tushar M. Patel, Ankit D. Oza, Sandeep Kumar, Rahul Kumar Multidisciplinary Science Journal, 2025 In contemporary times, plastic waste recycling has emerged as a crucial trend, presenting significant potential for plastic reformulation and recyclability. Waste plastic, owing to its high calorific value and abundance, serves as a promising energy source. Through the pyrolysis process, plastic waste can be converted into pyrolysis oil, which exhibits properties akin to conventional diesel fuel and can be seamlessly integrated into engines. This study investigates the synthesis of waste plastic oil (WPO) via pyrolysis using a diverse feedstock comprising various types and grades of plastic. The resulting oil, resembling diesel in characteristics, is evaluated for its performance in a compression ignition (CI) engine equipped with a variable compression ratio.Experimental tests are conducted using blends of WPO and diesel ranging from 0% to 100%, across different engine loads spanning from partial to full load conditions (2 kg to 12 kg). The combustion characteristics, engine performance metrics, and emission profiles are meticulously analyzed and compared against those of conventional diesel fuel. The findings indicate that the engine exhibits comparable performance with WPO at higher loads, akin to that with diesel. However, at lower loads, an extended delay period is observed, contributing to engine stabilization.These results underscore the potential of renewable plastic oil as a viable alternative fuel for diesel engine applications, particularly under specific operating conditions. The study provides valuable insights into the feasibility and performance implications of integrating waste plastic oil into compression ignition engines, contributing to the ongoing discourse on sustainable energy solutions and waste management practices.
Space cooling through dual-axis paraboloid solar concentrator system Mukesh Kumar Gupta, Rahul Kumar, Amit Kumar Thakur, Rajesh Singh, Vineet Singh Sikarwar Energy Sources Part A Recovery Utilization and Environmental Effects, 2025 The design parameters, structure and component materials significantly impact a solar dish concentrator system’s performance, operation, and maintenance. Recently, solar cooling has emerged as a cutting-edge technology, particularly advantageous for regions with abundant sunlight. This study aims to assess the efficacy of a solar cooling system by employing a combination of a parabolic trough collector and a storage tank to develop a numerical model to evaluate the system’s dynamic performance. Utilizing a 12 m2 aperture parabolic dish concentrator (PDC) module, it is successfully demonstrated that approximately 24 m2 of building space can be effectively cooled for around 12 h/day throughout the entire summer season. The optimal specific mass flow rate is 0.028 kg/cm2, with optimum storage tank volume at 0.34 m3. A single PDC module with a 300-l tank and 95.3 kWh of solar energy per day can provide 3 kW of cooling with a solar performance coefficient of 0.52 to 0.67. UNDP has provided INR 8 lakhs (15% of benchmark cost) and VAM of INR 6 lakhs (10%) of INR 30 lakhs in financial support. This study significantly promotes solar-assisted space cooling as a sustainable and eco-friendly technology.
DESIGN AND DYNAMIC RESPONSE OF SWIRL COAXIAL INJECTORS FOR LOX-METHANE ROCKET ENGINE Rahul Kumar, Abhishek Sharma, Aravind Vaidyanathan, T. John Tharakan, S. Sunil Kumar International Journal of Fluid Mechanics Research, 2025 The optimization of injector dynamics is essential for enhancing performance, reliability, and safety in rocket engines. This study examines the dynamics of an in-house-designed, coaxial swirl injector for a high-pressure LOx-CH 4 rocket system, presenting a novel methodology for a swirl injector design that incorporates both flow and geometric parameters. A comprehensive parametric study, based on Bazarov's analytical framework, is conducted to assess the influence of geometric design variables on injector dynamics. The findings indicate that increasing the vortex chamber length (L v ) reduces the dynamic response and shifts the resonance peak to lower frequencies. An optimal radius ratio (R rt ) between 1.2 and 1.8 is identified to achieve a balanced dynamic response. Additionally, variations in the convergence angle (β) have minimal impact on the injector's overall dynamics, with a 45° angle found to be optimal for manufacturing purposes. This study offers crucial design recommendations for developing stable swirl injectors with an optimized dynamic response, providing valuable insights for improving injector performance and ensuring stability in high-pressure rocket systems.
Prospects of Renewable Energy Scenario in India Rahul Kumar, Nishikant Kishor Dhapekar, Rajesh Tiwari, Y. Anupam Rao, Renuka Shyam Narain, Anil Singh Yadav, Abhishek Sharma Energy Systems in Electrical Engineering, 2024
