Investigating the thermodynamic limits of dimethyl ether - dodecane blends for heavy-duty diesel engines: An RSM-based numerical modeling of adiabatic flame temperature and specific exergy

Öz

In this study, the effect of substituting up to 60 wt% Dimethyl Ether into dodecane (C₁₂H₂₆), representing conventional diesel fuel, on the theoretical thermodynamic limits of combustion was numerically investigated. To eliminate the masking effect of mechanical and thermal losses inherent in physical engine tests, a zero-dimensional (0D) thermodynamic equilibrium model based on the Gibbs Free Energy Minimization principle was established using DWSIM software. Adiabatic Flame Temperature and Specific Exergy data, obtained at various excess air ratios (0.8, 0.95, 1.10 and 1.4), were statistically analyzed via Response Surface Methodology (RSM). ANOVA results demonstrated that substituting up to 60 wt% DME into the blend did not lead to a statistically significant degradation in the maximum combustion temperature and the work potential (exergy) of the system (P > 0.05). The excess air ratio was identified as the sole parameter dominating both thermodynamic responses (P < 0.001). Consequently, new second-order empirical equations (surrogate models) with high predictive accuracy for AFT (R² = 91.61%) and Specific Exergy (R²= 88.56%) were introduced to the literature, enabling engine designers to directly compute the potential of fuel blends without requiring computationally expensive thermodynamic simulations. These findings indicate that DME is a promising alternative fuel that preserves the theoretical thermodynamic limits and maximum work potential of the combustion products. However, realizing this potential in practical applications requires accounting for real-engine dynamics such as spray atomization, combustion kinetics, and heat transfer, which dictate the actual mechanical power output.

Anahtar Kelimeler

• Dimethyl Ether (DME)
• Thermodynamic equilibrium
• Gibbs free energy minimization
• Response surface methodology (RSM)
• Zero-dimensional (0D) thermodynamic model

Kaynakça

1. [1] Teixeira ACR, Machado PG, Collaço FM de A, Mouette D. Alternative fuel technologies emissions for road heavy-duty trucks: a review. Environmental Science and Pollution Research 2021; 28: 20954-20969.
2. [2] Reg (EU) 2024/1257. Regulation (EU) 2024/1257 of the European Parliament and of the Council of 24 April 2024 on type-approval of motor vehicles and engines with respect to emissions and battery durability (Euro 7). 2024.
3. [3] Ma W, Gao S, Liu H, Li D. The improvements of a diesel engine fueled with renewable and sustainable diesel/n-butanol/polyoxymethylene dimethyl ethers blended fuels at high altitudes. Energy 2024; 289.
4. [4] Chen H, He J, Chen Z, Geng L. A comparative study of combustion and emission characteristics of dual-fuel engine fueled with diesel/methanol and diesel-polyoxymethylene dimethyl ether blend/methanol. Process Safety and Environmental Protection 2021; 147: 714-722.
5. [5] Uddin MM, Simson A, Wright MM. Techno-economic and greenhouse gas emission analysis of dimethyl ether production via the bi-reforming pathway for transportation fuel. Energy 2020; 211: 119031.
6. [6] Skorikova G, Saric M, Sluijter SN, van Kampen J, Sánchez-Martínez C, Boon J. The techno-economic benefit of sorption enhancement: evaluation of sorption-enhanced dimethyl ether synthesis for CO2 utilization. Frontiers in Chemical Engineering 2020; 2.
7. [7] Fedeli M, Negri F, Manenti F. Biogas to advanced biofuels: techno-economic analysis of one-step dimethyl ether synthesis. J Clean Prod 2022; 376: 134076.
8. [8] Im-orb K, Arpornwichanop A. Comparative techno-economic assessment of bio-methanol and bio-DME production from oil palm residue. Energy Convers Manag 2022; 258: 115511.

9. [9] Zhang Z, Tian J, Li J, Lv J, Wang S, Zhong Y, et al. Investigation on combustion, performance and emission characteristics of a diesel engine fueled with diesel/alcohol/n-butanol blended fuels. Fuel 2022; 320.
10. [10] Subramanian B, Thangavel V. Experimental investigations on performance, emission and combustion characteristics of diesel-hydrogen and diesel-HHO gas in a dual fuel CI engine. Int J Hydrogen Energy 2020; 45: 25479-25492.
11. [11] Tan D, Meng Y, Tian J, Zhang C, Zhang Z, Yang G, et al. Utilization of renewable and sustainable diesel/methanol/n-butanol (DMB) blends for reducing the engine emissions in a diesel engine with different pre-injection strategies. Energy 2023; 269.
12. [12] Taghavifar H, Nemati A, Walther JH. Combustion and exergy analysis of multi-component diesel-DME-methanol blends in HCCI engine. Energy 2019; 187: 115951.
13. [13] Zhang J, Huang Z, Han D. Exergy losses in auto-ignition processes of DME and alcohol blends. Fuel 2018; 229: 116-125.
14. [14] Hussam WK, Nabi MN, Rasul MG, Chowdhury AA, Rashid F, Islam N. Innovative insights into engine performance and emissions - a numerical and experimental investigation of aliphatic hydrocarbons and renewable dimethyl ether. Case Studies in Thermal Engineering 2025; 72: 106367.
15. [15] Kumar AN, Kishore PS, Raju KB, Ashok B, Vignesh R, Jeevanantham AK, et al. Decanol proportional effect prediction model as additive in palm biodiesel using ANN and RSM technique for diesel engine. Energy 2020; 213.
16. [16] Aytav E. Utilization of RSM to optimize the performance and emissions of a single cylinder diesel engine using waste hazelnut biodiesel. Case Studies in Thermal Engineering 2024; 58.
17. [17] Elkelawy M, El Shenawy EA, Bastawissi HA-E, Shams MM, P. V. E, Balasubramanian D, et al. Predictive modeling and optimization of a waste cooking oil biodiesel/diesel powered CI engine: an RSM approach with central composite design. Sci Rep 2024; 14.
18. [18] Pitchaiah S, Juchelková D, Sathyamurthy R, Atabani AE. Prediction and performance optimisation of a DI CI engine fuelled diesel-Bael biodiesel blends with DMC additive using RSM and ANN: energy and exergy analysis. Energy Convers Manag 2023; 292.
19. [19] Sayyed S, Das RK, Kulkarni K. Energy and exergy analyses of multiple biodiesel blended diesel engine. J Energy Resour Technol 2023; 145.
20. [20] Ma B, Yao A, Yao C, Wu T, Wang B, Gao J, et al. Exergy loss analysis on diesel methanol dual fuel engine under different operating parameters. Appl Energy 2020; 261: 114483.
21. [21] Mao Y, Raza M, Wu Z, Zhu J, Yu L, Wang S, et al. An experimental study of n-dodecane and the development of an improved kinetic model. Combust Flame 2020; 212: 388-402.
22. [22] He Z, Shen Y, Wang C, Zhang Y, Wang Q, Gavaises M. Thermophysical properties of n-dodecane over a wide temperature and pressure range via molecular dynamics simulations with modification methods. J Mol Liq 2023; 371: 121102.
23. [23] Yan T, Wang P, Liu J, Zhang J, Zhang L. Theoretical insight into the reaction kinetics of H-abstraction, isomerization and β-dissociation in n-dodecane combustion. Aerosp Sci Technol 2026; 168: 110918.
24. [24] Nguyen TA, Pham TY, Le HC, Nguyen VG, Nguyen LH. Exploring the feasibility of dimethyl ether (DME) and LPG fuel blend for small diesel engine: a simulation perspective. International Journal of Renewable Energy Development 2024; 13: 559-571.
25. [25] Sreemahadevan S, Sivakumar KV, Palanisamy M. Evaluation of the open source process simulator DWSIM for bioprocess simulation. Periodica Polytechnica Chemical Engineering 2024; 68: 195-202.
26. [26] Ullah K, Asaad SM, Inayat A. Process modelling and optimization of hydrogen production from biogas by integrating DWSIM with response surface methodology. Digital Chemical Engineering 2025; 14: 100205.
27. [27] Abrams DS, Prausnitz JM. Statistical thermodynamics of liquid mixtures: a new expression for the excess Gibbs energy of partly or completely miscible systems. AIChE Journal 1975; 21: 116-128.
28. [28] Liu Q, Proust C, Gomez F, Luart D, Len C. The prediction multi-phase, multi reactant equilibria by minimizing the Gibbs energy of the system: review of available techniques and proposal of a new method based on a Monte Carlo technique. Chem Eng Sci 2020; 216: 115433.
29. [29] Ayad SMME, Vago CL, Belchior CRP, Sodré JR. Cylinder pressure based calibration model for engines using ethanol, hydrogen and natural gas as alternative fuels. Energy Reports 2021; 7: 7940-7954.
30. [30] Amirkhanyan N, Kharatyan S, Manukyan K, Aprahamian A. Thermodynamics and kinetics of solution combustion synthesis: Ni(NO3)2 + fuels systems. Combust Flame 2020; 221: 110-119.
31. [31] Varandas B, Oliveira M, Borges A. Analytical and numerical thermodynamic equilibrium simulations of steam methane reforming: a comparison study. Reactions 2024; 5: 246-259.
32. [32] Szargut J. Exergy method: technical and ecological applications. WIT Press, Southampton, Boston, 2005.
33. [33] Sayadzadeh ME, Samani MR, Toghraie D, Emami S, Eftekhari SA. Numerical study on pollutant emissions characteristics and chemical and physical exergy analysis in mild combustion. Energy 2023; 278: 128001.
34. [34] Ishaq Khan M, Maccioni L, Concli F. Energy and exergy analysis of conventional automobile engines: evaluation of waste heat recovery potential to drive parasitic loads. Energies (Basel) 2025; 18: 3264.
35. [35] Zhang R, Su W, Lin X, Zhou N, Zhao L. Thermodynamic analysis and parametric optimization of a novel S-CO2 power cycle for the waste heat recovery of internal combustion engines. Energy 2020; 209: 118484.
36. [36] Draper NR, Lin DKJ. Response surface designs. In: Ghosh S, Rao CR, editors. Handbook of Statistics, Vol. 13. Elsevier Science B.V., 1996.
37. [37] Myers RH, Montgomery DC, Anderson-Cook CM. Response surface methodology: process and product optimization using designed experiments. Fourth Edition, John Wiley & Sons, Inc., Hoboken, New Jersey, 2016.