Numerical comparison of H2/air catalytic combustion characteristic of micro–combustors with a conventional, slotted or controllable slotted bluff body

Energy ◽  
2019 ◽  
Vol 189 ◽  
pp. 116242 ◽  
Author(s):  
Yunfei Yan ◽  
Ying Liu ◽  
Lixian Li ◽  
Yu Cui ◽  
Li Zhang ◽  
...  
Author(s):  
Zhenkun Sang ◽  
Xiaojing Lv ◽  
Zemin Bo ◽  
Yiwu Weng

Ultra low calorific value gas (ULCVG) is hard to be realized by the conventional combustion technology. Most of them are discarded into atmosphere directly, causing the inadvertent waste and serous pollution. Currently, a new type gas turbine with catalytic combustion and rotary regenerator can be used to utilize these fuels and mitigate pollution. Differing from the conventional gas turbine, the chamber and regenerator of the new gas turbine is combined into one component, which is named rotary recuperative type catalytic chamber (RRTCC). The catalytic combustion is applied for RRTCC. The catalytic combustion characteristic of RRTCC is studied using the computational fluid dynamics (CFD). The results indicate that when the inlet velocity is 20 m/s, the methane conversion rate is 90%∼95%, and the corresponding outlet gas temperature is 1030∼1200K. When there is a variation of ±25% in the inlet velocity, the variation of methane conversation rate is −15% and 5% respectively, and the variation of outlet gas temperature is −6% and 2% respectively. Additionally, it is found that the hotspot temperature of combustor wall decreases with the increase of inlet velocity. The lowest value of hotspot temperature is about 1000K, which is higher than the ignition temperature of CH4. Therefore, the existence of hotspot temperature is useful for the catalytic ignition. The temperature distribution on the combustion side exhibits a smoking-pipe-like shape, as well as the recuperative side. The results can provide data reference for RRTCC design.


2019 ◽  
Vol 26 (8) ◽  
pp. 2214-2223 ◽  
Author(s):  
Jia-qiang E ◽  
Jiang-hua Wu ◽  
Teng Liu ◽  
Jing-wei Chen ◽  
Yuan-wang Deng ◽  
...  

Author(s):  
Dana Ganor-Stern

Past research has shown that numbers are associated with order in time such that performance in a numerical comparison task is enhanced when number pairs appear in ascending order, when the larger number follows the smaller one. This was found in the past for the integers 1–9 ( Ben-Meir, Ganor-Stern, & Tzelgov, 2013 ; Müller & Schwarz, 2008 ). In the present study we explored whether the advantage for processing numbers in ascending order exists also for fractions and negative numbers. The results demonstrate this advantage for fraction pairs and for integer-fraction pairs. However, the opposite advantage for descending order was found for negative numbers and for positive-negative number pairs. These findings are interpreted in the context of embodied cognition approaches and current theories on the mental representation of fractions and negative numbers.


Author(s):  
M. A. Adzmi ◽  
A. Abdullah ◽  
Z. Abdullah ◽  
A. G. Mrwan

Evaluation of combustion characteristic, engine performances and exhaust emissions of nanoparticles blended in palm oil methyl ester (POME) was conducted in this experiment using a single-cylinder diesel engine. Nanoparticles used was aluminium oxide (Al2O3) and silicon dioxide (SiO2) with a portion of 50 ppm and 100 ppm. SiO2 and Al2O3 were blended in POME and labelled as PS50, PS100 and PA50, PA100, respectively. The data results for PS and PA fuel were compared to POME test fuel. Single cylinder diesel engine YANMAR TF120M attached with DEWESoft data acquisition module (DAQ) model SIRIUSi-HS was used in this experiment. Various engine loads of zero, 7 N.m, 14 Nm, 21 N.m and 28 N.m at a constant engine speed of 1800 rpm were applied during engine testing. Results for each fuel were obtained by calculating the average three times repetition of engine testing. Findings show that the highest maximum pressure of nanoparticles fuel increase by 16.3% compared to POME test fuel. Other than that, the engine peak torque and engine power show a significant increase by 43% and 44%, respectively, recorded during the PS50 fuel test. Meanwhile, emissions of nanoparticles fuel show a large decrease by 10% of oxide of nitrogen (NOx), 6.3% reduction of carbon dioxide (CO2) and a slight decrease of 0.02% on carbon monoxide (CO). Addition of nanoparticles in biodiesel show positive improvements when used in diesel engines and further details were discussed.  


2002 ◽  
Vol 7 (1) ◽  
pp. 31-42
Author(s):  
J. Šaltytė ◽  
K. Dučinskas

The Bayesian classification rule used for the classification of the observations of the (second-order) stationary Gaussian random fields with different means and common factorised covariance matrices is investigated. The influence of the observed data augmentation to the Bayesian risk is examined for three different nonlinear widely applicable spatial correlation models. The explicit expression of the Bayesian risk for the classification of augmented data is derived. Numerical comparison of these models by the variability of Bayesian risk in case of the first-order neighbourhood scheme is performed.


2016 ◽  
Vol 10 (6) ◽  
pp. 390 ◽  
Author(s):  
Qummare Azam ◽  
Mohd Azmi Ismail ◽  
Nurul Musfirah Mazlan ◽  
Musavir Bashir

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