用旋喷冒浆测控旋喷体液固含量及喷射直径

对旋喷体进行定量分析是十分必要的。本文以实践经验，结合数学方法对旋喷冒浆进行定量分析，以确定旋喷体的液固含量、旋喷孔口冒浆量、旋喷喷射直径，取得了好的效果。

高喷凝结体有效喷射长度的浅析

阐述高压射流破坏土的机理 ,并通过对实测资料的统计分析 ,得出砂土地层中喷射直径与提升速度、喷射压力、土层强度、摆动角度等主要影响因素的估算公式。

高喷桩体直径的估算

阐述了高压射流破坏土的机理 ,影响喷射直径的主要因素有 :土粒组成、土的强度、喷射介质的压力、提升速度、喷射管的转动频率、摆动角度、喷射介质的种类等。对大量的实测资料进行了统计分析 ,得出了砂土地层中采用三管法施工的喷射直径与喷射管的提升速度、摆动角度、喷射压力、土层强度等主要影响因素的估算公式。应用这些估算公式可显著提高设计的合理性和精确度。

砂土地层中单个高喷喷射体有效长度的分析

文章首先阐述了高压射流破坏土的机理,然后通过对实测资料的统计分析,得出了砂土地层中喷射直径与提升速度、喷射压力、土层强度。

喷嘴直径匹配对PDC钻头流场特性影响

在石油钻井过程中,PDC钻头利用水力射流的能量进行破岩和清岩,而中心喷嘴与外围喷嘴直径的变化将直接影响井底流场特性。文章利用三维建模和数值模拟软件,建立了PDC钻头实体模型,并将其导入数模软件,分析215.9 mm PDC钻头喷嘴直径对井底流场的影响规律。模拟结果表明,当中心喷嘴直径为12.70 mm时,外围喷嘴直径为8.74~11.13 mm能使PDC钻头井底流场最优。而当外围喷嘴直径为11.13 mm时,中心喷嘴的直径应大于或等于11.13 mm才适合PDC钻头流场。利用该研究结论,可以辅助PDC钻头设计,提高钻头水力能量的利用率进而提高机械钻速。

Fluid flow characteristics of single inclined circular jet impingement for ultra-fast cooling

The fluid flow characteristics of the single bunch inclined jet impingement were investigated with different jet flow velocities,nozzle diameters,jet angles and jet-to-target distances for ultra-fast cooling technology.The results show that the peak pressure varying significantly from nearly 0.5 to above 13.4 kPa locates at the stagnation point with different jet diameters,and the radius of impact pressure affected zone is small promoted from 46 to 81 mm in transverse direction,and 50 to 91 mm in longitude direction when the jet flow velocity changes from 5 to 20 m/s.However,the fluid flow velocity is relatively smaller near the stagnation point,and increases gradually along the radius outwards,then declines.There is an obvious anisotropic characteristic that the flow velocity component along the jet direction is about twice of the contrary one where the jet anlge is 60°,jet diameter is 5 mm,jet length is 8 mm and jet height is 50 mm.

Performance of R141b Ejector with Thermal Storage for Solar Air Conditioning

This paper was designed to determine the performance of the R 141 b ejector includes analysis in economics. The first step is to determine the operating condition and ejector geometry through computer calculation program. That found at the generator temperature 84 ℃ and evaporator temperature 8 ℃, diameter of nozzle throat is 2 mm, diameter of nozzle exit is 8 mm, diameter of mixing chamber inlet is 25 mm, diameter of constant area section is 8 mm. Area of evacuated solar collector is 10 m2, thermal storage tank size is 0.33 m3, cold thermal storage size is 2.3 m3. The entrainment ratio and COP （coefficient of performance） of computer calculation program are 0.295 and 0.235, respectively. The second step ejector is fabricated and equipped to solar ejector refrigeration system, it is found that, average COP is 0.265. The economics analysis of solar ejector cooling system are invested in the investment cost was 158,158 baht. When calculating payback period was 7.73 years, the return value on a NPV （net present value） was 60,872.63 baht of lifetime of the system throughout a period of 15 years, and IRR （internal rate of return） is 13.57%.

Development of Breakup Model for Large Eddy Simulation of Diesel Spray

Diesel spray is injected at high pressure. So, upper stream region of spray is high Weber number condition. However, even if the fuel is injected at high pressure, the downstream region of spray is corresponding to relatively low Weber number condition. Thus, KH （Kelvin-Helmholtz） model modeled for high Weber number conditions and MTAB （modified Taylor analogy breakup） model are used for primary and secondary breakup processes respectively. This study is focused on the development of new hybrid breakup model The calculations are performed by LES （large eddy simulation） incorporated into KIVA code. LES of non-evaporating diesel spray are performed using KH ＆ RT （Rayleigh-Taylor） model, MTAB model and KH-MTAB model. Then, LES with these models were compared with experimental results. As the result, the availability of KH-MTAB model is showed. It is found that KH-MTAB is good agreement with experimental results of penetration and SMD （Sauter mean diameter） in relatively low density conditions.

Self-extinguishing behavior of Kerosene Spray Fire in a Completely Enclosed Compartment

The self-extinguishing behavior of kerosene spray fire was investigated in a completely enclosed compartment with the size of 3 m× 3 m × 3.4 m. The spray was generated by locating one BETE nozzle at the center of the bottom wall. A series of spray fire videos were obtained by changing BETE nozzle type and injecting pressure. The results show that spray ftre undergoes four stages： the growth stage, the quasi-steady stage, the stretch stage and the self-extinguishing stage. Consumption of large quantities of oxygen causes spray fire to first be stretched and then quench. In this process, fire base migrates away from spray region and leads to the emergence of ghost- hag fire. Ghosting fire promotes the instability of spray fire and large fluctuation of its height, which provides help to its self-extinguishing. With increasing the injecting pressure or the nozzle diameter, the self-extinguishing time decreases. It is found that the self-extinguishing time is approximately in inverse relation with injecting flow rate. Additionally, we also observed the occurrence of two-phase de flagration just after ignition, and it accelerates the spray fire growth and induces a larger fire height than the following quasi-steady spray fire. The deflagration turns stronger with increasing the injecting pressure.

Contributions of the Secondary Jet to the Tangential Velocity Distribution and to the Collection Efficiency of the Fixed Guide Vane Type Axial Flow Cyclone Dust Collector

In order to control the maximum tangential velocity V?m(m/s)of the turbulent rotational air flow and the collection efficiencyηc(%)using the fly ash of the mean diameter X R50=5.57?m,two secondary jet nozzles were installed to the body of the axial flow cyclone dust collector with the body diameter D1=99mm.Then in order to estimate V?m(m/s),the conservation theory of the angular momentum flux with Ogawa combined vortex model was applied.The comparisons of the estimated results of V?m(m/s)with the measured results by the cylindrical Pitot-tube were shown in good agreement.And also the estimated collection efficienciesηcth(%)basing upon the cut-size Xc(?m)which was calculated by using the estimated V?m(m/s)and also the particle size distribution R(Xp)were shown a little higher values than the experimental results due to the re-entrainment of the collected dust.The best method for adjustment ofηc(%)related to the contribution of the secondary jet flow is principally to apply the centrifugal effect?c(1).Above stated results are described in detail.