In this paper, the effects of injection parameters on combustion and particulate size distribution of partially premixed combustion (PPC) fuel with n-butanol were investigated experimentally. High concentrations of particle emission for the n-butanol PPC combustion are observed. The particle sizes are primarily concentrated within 64nm. With the advance of the start of injection (SOI) timing, more particles are formed and the particulate size distribution curve shifts towards right (larger size). In addition, the pilot-main injection strategy can effectively reduce the maximum pressure rise rate (MPRR). Furthermore, through adopting appropriate injection parameters, the MPRR and particle number can be reduced simultaneously, while still maintaining a comparable indicated thermal efficiency compared to the single injection strategy.
Ultra-high heat flux cooling has become a research hotspot owing to its wide application in thermal engineering fields. Only by exploring its internal physical mechanism and calculating the CHF (critical heat flux) of different surfaces, can the necessary theoretical basis be provided for the design and optimization of pool boiling heat exchange in engineering applications. Previous models cannot accurately predict CHF value due to the limitations of their physical models. In this paper, a new theoretical physical model was obtained to predict CHF value of pure liquid on a heated surface. The theoretical model proposed a new CHF trigger mechanism based on the bubble behavior near the heater surface. A three-dimensional force balance of a separated bubble was analyzed at CHF condition to derive the analytical correlation for CHF value. The correlation considers the effect of hydraulic pressure, surface tension, liquid properties as well as the contact angle of the heater surface. The predicted values of CHF value on heated surfaces obtained from the present model were found in agreement with existing experimental data within a wide range. It is shown that CHF is mainly affected by factors of adhesion force and hydraulic pressure.
This work proposes a novel design incorporating a passive heat recovery device into a windcatcher and investigates its performance using numerical and experimental analysis. Numerical modelling and experimental testing were used to characterise the radial blade design of the heat recovery rotary wheel in terms of performance. Two configurations of the radial blades provide data that can be used to assess how air velocity is affected by the design, the pressure drop across the device and the heat transfer capabilities of the radial blades. To further assess the potential of the proposed devices, it was incorporated into a multi-directional windcatcher ventilating a small room. Despite the blockage of the rotary heat recovery wheel, it was able able to provide adequate ventilation. In addition to sufficient ventilation, the heat in the exhaust airstreams was captured and transferred to the incoming airstream, raising the temperature between 0.5-4K depending on the indoor/outdoor conditions, this passive recovery has the potential to reduce demand on space heating systems.
Owing to the rapid development of the global economy, the demand for energy and water resources is the main global challenge in the 21st century. This article focuses on the consumption and transfer of the water resources in China’s West–East electricity transmission project. The input–output method is employed to construct a water footprint assessment model for this project. Results show that 606.4 billion kWh of electricity and 2.5 billion m3 of virtual water were transferred from the western to eastern region in 2016. Coordinated policy making the optimal use of water resources for energy generation needs to be further discussed for promoting sustainable regional development.
Energy is vital in modern society and almost in every production process for sustainable economic growth. China is developing country and poverty is always higher especially in rural areas. The study examines the relationship between renewable energy (RE), as whole & by sources solar, wind, geothermal, foreign direct investment (FDI) and poverty alleviation (PA) for sustainable economic development in China. Ordinary Leas Square OLS and Fully Modified OLS methods are use in this study. The results found that there is long run relationship between variables and increase in investment and renewable energy sources production to reduce the poverty. Poverty causes lack of income and production resources, poor infrastructure, inequality and social discrimination. China first needed to overcome these issues for poverty alleviation for sustainable economic development.
The dynamic responses of Solid oxide fuel cell (SOFC) power system across multiple time scales from micro seconds to minutes due to the phenomena of different nature that governing. Mismatching the time scale differences may lead to fuel starving and thermal shock during the fast load following. In this paper, the singular perturbation (SP) theory was introduced for modeling the mutli-time scale system dynamics. The dynamic model of SOFC power system in the coordinates in which slow and fast variables were explicitly defined and exactly separated. The resulting multi-single time scale models facilitate a better understanding of system dynamics, key parameters and their interactions, such as temperature, mass flow rate, current and voltage. Effective SOFC power system controllers can be designed based on these results.
Hydro power production strictly depends on the geography and weather peculiarity of locations where power plants are settled. In this paper, we produce long term estimates of hydro power capacity factors for all European countries based on future climate scenarios. We use machine learning techniques for formalizing models able to capture the complex relation between climate variables and energy production on a European scale and use the results of regional and global climate models for future projections.
The combustion characteristics of biomass in the packed bed is investigated based on the CFD-discrete element method (DEM). During the combustion process, the biomass particle experienced drying, pyrolysis, combustion and cooling. The mass loss leads to the change of particle density and diameter, as the remnant composition is mainly ash. In this work, the shrinkage of packed biomass volume is modelled as the particle diameter is decreased based on DEM. The different effects of compositions in the particle on particle diameter are considered. The simulation results show good agreement with the experimental measurement.
The long‐term production of U.S. tight oil is forecast by using a composite model combining the Generalized Weng and Gompertz models. We show that U.S. tight oil production is likely to reach a peak within ten years, between 2019 and 2028, at a production rate between 7 and 13 million barrels per day (Mb/d), depending on the size of the ultimately recoverable resource (URR) estimate. Our most‐likely ‘medium‐case’ URR scenario suggests the peak year is probably around 2025, at a production rate of about 10 Mb/d. Comparing our results with those of the U.S. Energy Information Administration (EIA) suggests that the EIA is over‐optimistic in its long‐term production forecast of U.S. tight oil.
Aiming at the demand of comprehensive vulnerability assessment in shipboard power system security defense, the paper proposed a vulnerability status description model of shipboard power system. The structure and physical properties of shipboard power network were fully analyzed. The product space which was called shipboard power network comprehensive vulnerability index set was established by degrees, betweenness, maximum connection sub-diagram scale, reliability indexes. Secondly, the normalized index sets were compactness and thepnormon the compactness sets were continuous were proved in this paper. The norm of vulnerability index was vulnerability output equation of shipboard power system. Using the norm on the product space, multi-scale integrated shipboard power network vulnerability norm was proposed, and the comprehensive structure performance evaluation of the shipboard power system network was formed. The index describes the change tendency of the shipboard power network comprehensive vulnerability. Finally, the test on a certain type of shipboard power network demonstrates the validity of the model.