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Experimental characterisation of hollow-cone hydrogen jet behaviour under engine-like conditions

2026-08-21T02:01:03Z

Title: Experimental characterisation of hollow-cone hydrogen jet behaviour under engine-like conditions Authors: Dong, Shuo; Feng, Yizhuo; Nagarajan, Raghul; Biswal, Abinash; Jiang, Changzhao; Wang, Xinyan; Zhao, Hua Abstract: Internal combustion engines equipped with direct injection (DI) of hydrogen represent a promising pathway toward carbon-neutral transportation. This work presents a systematic experimental investigation of hollow-cone hydrogen jet dynamics generated by an outward-opening injector using high-speed schlieren imaging, integrating jet momentum measurements. The hydrogen jet evolution is identified as a two-stage process, i.e., near-nozzle underexpanded structures dominated by pressure-ratio effects and a subsequent self-similar dense-jet stage governed by momentum. The pressure-ratio-dominant and momentum-dominant scaling laws are evaluated for these two stages, clarifying the governing mechanisms of hollow-cone hydrogen jet development. Furthermore, a quantitative evaluation of hydrogen mixing behaviour is conducted with a constant injected mass under different injection pressures (Pinj). The results show that Pinj has a limited influence on jet shapes during injection, whereas higher Pinj improves spatial mixture homogeneity. The difference in homogeneity can be reduced by allowing a longer mixing time after the end of injection. Description: Supplementary data are available online at: https://www.sciencedirect.com/science/article/pii/S0360319926037195#appsec1 .

Correction: From corporate greenhouse gas inventories to design-relevant LCAs: an integrated framework for industrial decarbonization

2026-08-20T02:01:27Z

Title: Correction: From corporate greenhouse gas inventories to design-relevant LCAs: an integrated framework for industrial decarbonization Authors: Don Merenchige, Upendra Arjeewani Weerathunga; Wang, Bin; Ji, Shouxun Abstract: During typesetting of this article in place of Fig. 3, Fig. 4 was duplicated. The missing Fig. 3 is shown below: Example of data collection granularity across emission sources, illustrating hierarchical categorization from emission source to client level. The framework enables detailed activity data collection, for example, raw materials are traced from material type and grade to product type, accurate emission allocation across both organizational and product-level inventories The original article has been corrected. Description: Data availability: The data supporting the findings of this case study were provided by the participating organization under confidentiality agreements. As such, the data are not publicly available in accordance with the organization’s data disclosure policy.; The corrected manuscript is archived below (59 pp.) under an embargo period of 12 months.

Pressure-regulated pool boiling for lithium-ion batteries based on a thermo-lifetime-economic coupling framework

2026-08-20T02:00:56Z

Title: Pressure-regulated pool boiling for lithium-ion batteries based on a thermo-lifetime-economic coupling framework Authors: Wang, Xiang; Li, Liang; Tassou, Savvas A Abstract: Pool boiling cooling offers strong potential for lithium-ion battery thermal management due to its high-efficiency phase-change heat transfer. However, most existing studies are limited to atmospheric pressure, and the coupled effects of pressure on thermal behaviour, battery lifetime, and economic performance remain unclear. In this study, a thermo-lifetime-economic coupling model is developed and experimentally validated through pressure-controlled pool boiling cooling of a battery module over a pressure range of 20–100 kPa. The results show that pool boiling significantly outperforms natural air-cooling, reducing the maximum temperature from 88.8 °C to 45.6 °C (48.6%) and the temperature difference from 9.3 °C to 3.1 °C (66.7%) at 2.5C. Further pressure reduction enhances thermal performance by lowering the saturation temperature and promoting earlier nucleate boiling. When the pressure decreases from 100 kPa to 20 kPa, the maximum temperature and temperature difference are further reduced by 26.3% and 38.7%, respectively, leading to a lifetime improvement of up to 65.1%. However, this improvement is accompanied by a substantial increase in auxiliary power consumption, which rises by more than 14.6 times, resulting in a strong thermo-economic trade-off with diminishing returns at low pressures. Furthermore, system scale critically affects economic feasibility. Pressure reduction increases cost at small scales but becomes favourable beyond a critical scale due to the growing contribution of lifetime-related cost. These results show that pressure regulation can improve pool boiling battery cooling, but the operating pressure should balance thermal performance, lifetime, and energy consumption. Description: Data availability: Data will be made available on request.

Dynamic transient control of hydrogen direct-injection SI engines: effects of ramp duration on engine performance and abnormal combustion

2026-08-19T02:01:03Z

Title: Dynamic transient control of hydrogen direct-injection SI engines: effects of ramp duration on engine performance and abnormal combustion Authors: Zaman, Zayne; Mohamed, Mohamed; Wang, Xinyan; Zhao, Hua; Harrington, Anthony; Hall, Jonathan Abstract: Hydrogen internal combustion engines offer a route to near-zero carbon on-road transport while preserving existing engine manufacturing and calibration know-how. Translating that potential into real-world driving, however, depends on transient control; steady-state maps alone cannot guarantee either safe operation or low NOx emissions during load steps. This paper reports a controlled transient sweep on a 0.4 L single-cylinder direct-injection spark-ignition hydrogen research engine. Five ramp durations (1.38, 1.08, 0.84, 0.48 and 0.24 s) were evaluated at a constant engine speed of 2,000 rpm with a target relative air–fuel ratio of 2.75 under closed-loop feedback control. The measurements track injection pulse width, spark timing, boost, lambda, IMEP, peak in-cylinder pressure and the maximum pressure rise rate (𝘙_max) through each transient. As ramp duration is shortened, lambda excursions and air-path overshoot grow rapidly: at 0.24 s the in-cylinder pressure overshoot approaches the mechanical safety limit, IMEP overshoots the steady-state target by about 22 %, and 𝘙_max exceeds the 600 kPa/°CA calibrated threshold. With a ramp of 0.48 the most hazardous 𝘙_max peak at roughly 1,000 kPa/°CA is caused, demonstrating that fastest is not always most damaging. Only the 1.38 s baseline keeps all combustion-severity metrics inside their reliability envelope. A feed-forward fuelling term scaled by the rate of manifold pressure change dP/dt is proposed to close the transient lambda gap; with physical implementation and experimental validation proposed as a future optimisation step. The results identify pressure-gradient management as the binding constraint for transient calibration of lean DI hydrogen engines. Description: Data availability: Data will be made available on request.