scholarly journals Numerical Simulation and Design of a High-Temperature, High-Pressure Fluid Transport Pipe

2020 ◽  
Vol 10 (17) ◽  
pp. 5890
Author(s):  
Jiyoung Yoon ◽  
Junkyu Park ◽  
Jinhyoung Park
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
High Pressure ◽  
High Temperature ◽  
Low Temperature ◽  
Fluid Transport ◽  
Projectile Velocity ◽  
Gas Leakage ◽  
And Performance ◽  
High Temperature High Pressure

When designing a hand caliber with a high-temperature, high-pressure internal fluid transport pipe, reliability, safe use, and performance must be considered. Reliability refers to the stress caused by thermo-mechanical load; safe use refers to the low-temperature burns that might occur upon contact, and high-temperature burns caused by gas leakage occurring in the cylinder gap; and performance refers to projectile velocity. In this study, numerical simulation methods for heat transfer, structure analysis, and gas leakage are proposed so that solutions can be designed to account for the above three criteria. Furthermore, a hand-caliber design guide is presented. For heat transfer and structural analysis, mesh size, the transient convective heat transfer coefficient, and boundary conditions are described. Regarding gas leakage, methods reflecting projectile motion and determination of the molecular weight of the propellant are described. As a result, a designed hand caliber will have a high reliability, because the thermo-mechanical stress is lower than the yield stress. There will be little risk of low-temperature burns, but there will be a high temperature-burn risk, owing to gas leakage in the cylinder gap. The larger the cylinder-gap size, the greater the gas leakage and the smaller projectile velocity. The presented numerical simulation method can be applied to evaluate various aspects of other structures that require high-temperature, high-pressure fluid-transport pipes.

Usage of Nano Silica in Synthetic Based Mud: A Comparison Study for High Temperature High Pressure Well

2015 ◽  
Vol 789-790 ◽  
pp. 80-84
Author(s):  
Muhammad Aslam Md Yusof ◽  
Norazwan Wahid ◽  
Nor Hazimastura Hanafi
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Prolonged Exposure ◽  
Comparison Study ◽  
Nano Silica ◽  
Nanoparticles Concentration ◽  
And Performance ◽  
20 Nm ◽  
Rheology Modifier ◽  
High Temperature High Pressure

Synthetic based mud has been widely used in the drilling operation because of its good properties. However, prolonged exposure of the mud in high temperature causes degradation of the good mud properties because of chemical instability. Because of that concern, this study intends to improve the performance of SBM with nanosilica at different concentration in high temperature high pressure (HTHP) applications. nanosilica with size of 10-20 nm has been selected for this study. The involving parameters in this study include the manipulation of nanoparticles concentration by total mud weight between 0 to 1.78 wt. %, and performance at temperature up to 350°F. The enhanced formulation has given significant benefits by reducing the filtration up to 41.67% and act as the rheology modifier in HTHP condition. Moreover, the optimum amount of nanosilica is 0.71% of total mud weight to avoid further rheological and filtration degradation.

Experimental investigation of wall heat transfer due to spray combustion in a high-pressure/high-temperature vessel

2021 ◽  
pp. 146808742110072
Author(s):  
Karri Keskinen ◽  
Walter Vera-Tudela ◽  
Yuri M Wright ◽  
Konstantinos Boulouchos
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
High Pressure ◽  
High Temperature ◽  
High Speed ◽  
Transfer Problem ◽  
Wall Heat Transfer ◽  
Gas Temperature ◽  
Reference Case ◽  
High Pressure High Temperature

Combustion chamber wall heat transfer is a major contributor to efficiency losses in diesel engines. In this context, thermal swing materials (adapting to the surrounding gas temperature) have been pinpointed as a promising mitigative solution. In this study, experiments are carried out in a high-pressure/high-temperature vessel to (a) characterise the wall heat transfer process ensuing from wall impingement of a combusting fuel spray, and (b) evaluate insulative improvements provided by a coating that promotes thermal swing. The baseline experimental condition resembles that of Spray A from the Engine Combustion Network, while additional variations are generated by modifying the ambient temperature as well as the injection pressure and duration. Wall heat transfer and wall temperature measurements are time-resolved and accompanied by concurrent high-speed imaging of natural luminosity. An investigation with an uncoated wall is carried out with several sensor locations around the stagnation point, elucidating sensor-to-sensor variability and setup symmetry. Surface heat flux follows three phases: (i) an initial peak, (ii) a slightly lower plateau dependent on the injection duration, and (iii) a slow decline. In addition to the uncoated reference case, the investigation involves a coating made of porous zirconia, an established thermal swing material. With a coated setup, the projection of surface quantities (heat flux and temperature) from the immersed measurement location requires additional numerical analysis of conjugate heat transfer. Starting from the traces measured beneath the coating, the surface quantities are obtained by solving a one-dimensional inverse heat transfer problem. The present measurements are complemented by CFD simulations supplemented with recent rough-wall models. The surface roughness of the coated specimen is indicated to have a significant impact on the wall heat flux, offsetting the expected benefit from the thermal swing material.

Study of high-pressure air jet controlled compression ignition with compound thermodynamic cycle for combustion and emission formation process

2020 ◽  
pp. 146808742096933
Author(s):  
Xiangyu Meng ◽  
Sicheng Liu ◽  
Jingchen Cui ◽  
Jiangping Tian ◽  
Wuqiang Long ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Low Temperature ◽  
Formation Process ◽  
Combustion Process ◽  
Thermodynamic Cycle ◽  
Compression Ignition ◽  
Temperature Reaction ◽  
Air Jet ◽  
High Temperature Reaction

A novel method called high-pressure air (HPA) jet controlled compression ignition (JCCI) based on the compound thermodynamic cycle was investigated in this work. The combustion process of premixed mixture can be controlled flexibly by the high-pressure air jet compression, and it characterizes the intensified low-temperature reaction and two-stage high-temperature reaction. The three-dimensional (3D) computational fluid dynamics (CFD) numerical simulation was employed to study the emission formation process and mechanism, and the effects of high-pressure air jet temperature and duration on emissions were also investigated. The simulation results showed that the NOx formation is mainly affected by the first-stage high-temperature reaction due to the higher reaction temperature. Overall, this combustion mode can obtain ultra-low NOx emission. The second-stage high-temperature reaction plays an important role in the CO and THC formation caused by the mixing effect of the high-pressure air and original in-cylinder mixture. The increasing air jet temperature leads to a larger high-temperature in-cylinder region and more fuel in the first-stage reaction, and therefore resulting in higher NOx emission. However, the increasing air jet temperature can significantly reduce the CO and THC emissions. For the air jet duration comparisons, both too short and too long air jet durations could induce higher NOx emission. A higher air jet duration would result in higher CO emission due to the more high-pressure air jet with relatively low temperature.

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