Tser-Son Wu

A New Alternative Fuel for Reduction of Polycyclic Aromatic Hydrocarbon and Particulate Matter Emissions from Diesel Engines

Abstract This study investigated the emissions of polycyclic aromatic hydrocarbons (PAHs), carcinogenic potential of PAH and particulate matter (PM), brake-specific fuel consumption (BSFC), and power from diesel engines under transient cycle testing of six test fuels: premium diesel fuel (PDF), B100 (100% palm biodiesel), B20 (20% palm biodiesel + 80% PDF), BP9505 (95% paraffinic fuel + 5% palm biodiesel), BP8020 (80% paraffinic fuel + 20% palm biodiesel), and BP100 (100% paraffinic fuel; Table 1). Experimental results indicated that B100, BP9505, BP8020, and BP100 were much safer when stored than PDF. However, we must use additives so that B100 and BP100 will not gel as quickly in a cold zone. Using B100, BP9505, and BP8020 instead of PDF reduced PM, THC, and CO emissions dramatically but increased CO2 slightly because of more complete combustion. The CO2-increased fraction of BP9505 was the lowest among test blends. Furthermore, using B100, B20, BP9505, and BP8020 as alternative fuels reduced total PAHs and total benzo[a]pyrene equivalent concentration (total BaPeq) emissions significantly. BP9505 had the lowest decreased fractions of power and torque and increased fraction of BSFC. These experimental results implied that BP9505 is feasible for traveling diesel vehicles. Moreover, paraffinic fuel will likely be a new alternative fuel in the future. Using BP9505 instead of PDF decreased PM (22.8%), THC (13.4%), CO (25.3%), total PAHs (88.9%), and total BaPeq (88.1%) emissions significantly.

Estimation of heat flux and thermal stresses in multilayer gun barrel with thermal contact resistance

In this study, a conjugate gradient method based on an inverse algorithm is applied to estimate the unknown time-dependent heat flux at the inner surface of gun barrel, in which the interlayer thermal contact resistance between the steel cylinder and the chrome coating is taken into account in the boundary conditions. While knowing the temperature history at the measuring position, no prior information is needed on the functional form of the unknown heat flux. The temperature data calculated from the direct problem are used to simulate the temperature measurement. The influence of measurement errors and initial guess values upon the precision of the estimated results is also investigated. Results show that an excellent estimation on the time-dependent heat flux, temperature distributions, and thermal stresses can be obtained for the case considered in this study.

PREDICTION OF UNKNOWN BASE HEAT FLUX IN AN ANNULAR FIN BY STRAIN MEASUREMENT

The conjugate gradient method of minimization with an adjoint equation is successfully used to solve the inverse problem in estimating the base heat flux of an annular fin. As long as knowing the strain history at any point of the fin, the time-varying base heat flux can be computed. In the analysis, the thermomechanical coupling effect is taken into account in the governing equation of heat conduction, and the convection heat transfer coefficient is assumed to be a function of the radius of the fin. The accuracy of the inverse analysis is examined by using simulated and inexact measurements obtained within the medium

Inverse Thermo-Mechanical Analysis of a Functionally Graded Fin

In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to estimate the unknown time-dependent base heat flux of a functionally graded fin from the knowledge of temperature measurements taken within the fin. Subsequently, the distributions of temperature and thermal stresses in the fin can be determined as well. It is assumed that no prior information is available on the functional form of the unknown base heat flux; hence the procedure is classified as the function estimation in inverse calculation. The temperature data obtained from the direct problem are used to simulate the temperature measurements. The influence of measurement errors and measurement location upon the precision of the estimated results is also investigated. Results show that an excellent estimation on the time-dependent base heat flux, temperature distributions, and thermal stresses can be obtained for the test case considered in this study.

Emissions in the exhaust of fishing boats after adding viscous agents into fuel oils.

In order to avoid the illegal use of fishing boat fuel A (FBFA) by traveling diesel vehicles (TDVs) in Taiwan, alternatives that are easily distinguished from premium diesel fuel (PDF) were prepared to evaluate their suitability. Two new ingredients, pyrolysis fuel oil (PFO) and residue of desulfurization unit (RDS), were added into FBFA and formed PFO0.5 and RDS0.5, respectively. Along with FBFA, these three fuels were analyzed for their chemical and physical properties. Furthermore, they were used by three fishing boats with different sizes, output powers, and weights. The engine performances and pollutant emissions were examined and monitored. Experimental results show that there are significant differences in appearance between PDF and the two new blended fuels (PFO0.5 and RDS0.5), and thus misuse or illegal use of FBFA could be substantially reduced. The fuel consumption, which is negatively related to the heating value of fuels, is in order of FBFA<PFO0.5=RDS0.5. In contrast with using FBFA in the three fishing boats, using RDS0.5 resulted in a decrease in CO and NO(x) emissions, while the PM emission factors (g bhp(-1) h(-1) and g L(-1)-fuel) were reduced by approximately 36% and 33%, respectively. Owing to the higher total aromatic content in PFO0.5 and RDS0.5, total-PAH concentrations in the exhausts from the three fishing boats using PFO0.5 and RDS0.5 were slightly (1.2 and 1.1 times, respectively) higher than for those using FBFA. Nevertheless, the estimated total BaP(eq) from the three fishing boats using RDS0.5 was 27.5, 19.5, and 8.25% lower than those using FBFA. With using PFO0.5, they were totally different, at 23.5, 2.79, and 2.58% higher. With regard to looking different to PDF, RDS0.5 is superior to PFO0.5, and is thus recommended as a better alternative to FBFA, particularly because it can help lower more emissions of CO, NO(x), PM and BaP(eq).

The energy efficiency tests of helical speed reducers

The motor speed reducer is a widespread used motor dynamic system product. Its energy specification, system design match, application operation and maintenance and so on, serious influence energy efficiency. The low efficiency type increases consumes the electrical power. But the user does not understand clearly. Therefore the energy efficiency test of the motor reducer is an urgent topic. In order to promote the motor speed reducer energy efficiency, two type helical gear speed reducers are tested. The motor power are 0.5hp, 1hp, 2hp and 3hp respectively and reducer ratio are 10, 20 and 30, they are arranged in pairs. A brake method is established to measure the energy efficiency of motor speed reducer. Two different brands speed reducers are measured for 24 samples. The test results showed that A brand helical gear speed reducer at 100% load condition the most high energy efficiency are 85.24% for 2 Hp and 1:10 ratio, and 93.45% for 3 Hp and 1:20 ratio, 92.55% for 3Hp and 1:30. ° For B brand helical gear speed reducer at 100% load condition the most high energy efficiency are 87.35% for 3 Hp and 1:10 ratio, and 88.4% for 3 Hp and 1:20 ratio, 91.48% for 3Hp and 1:30.

Development and temperature measurement of heat-recirculation gas combustors burning methane/air

A novel energy-economic and high efficiency heat recirculation combustor featuring “gas combustor, heat recirculation, and half-closed flame” was developed. The combustor includes three preheated modules, namely lower spiral channel without top cover, lower spiral channel with top cover, and upper spiral channel with top cover. The feed gas was methane and air mixture. The effects of fuel gas Reynolds Number (Rem), equivalent ratio (Φ), and preheat pattern on preheat temperature and flame combustion temperature of the heat recirculation gas combustor were investigated. The result of transient temperature measurement indicated that the preheat temperature increased linearly with combustion time, reaching up to 232.2°C in module C. Preheat pattern can affect mixed gas preheat temperature and flame combustion temperature. Among the three modules, the preheating effect of upper spiral channel with top cover was the best, the lower spiral channel with top cover was the second, and lower spiral channel without top cover module ranked the third.