High-temperature Flow Conditions Research Articles

Modeling steam flow in an injection tubing and analysis of flow regimes for high pressure-high temperature initial parameters

Steam injection is one of the popular methods for oil recovery enhancement. Success of this method to a significant extent depends on steam properties at a point of injection into a reservoir. A model of a steam flow through an injection tubing is developed. Heat losses from a flow to a surrounding formation are assumed to be quasi-steady state. A simplified model of a cylindrical reservoir at injection tubing end is introduced into the flow model to imitate realistic boundary conditions. Fluid thermodynamic parameters are calculated by using high-precision correlations. Computations performed are focused on high pressure – high temperature flow conditions. Effects of initial steam quality, fluid flow rate, different frictional pressure correlations and insulation thermal conductivity on distributions of steam quality, pressure and temperature along a vertical tubing are studied. An effect of initial steam conditions on a steam flow is also illustrated. A strong effect of hydrostatic pressure on a steam flow behavior is demonstrated.

A High-Temperature MEMS Surface Fence for Wall-Shear-Stress Measurement in Scramjet Flow.

A new variant of MEMS surface fence is proposed for shear-stress estimation under high-speed, high-temperature flow conditions. Investigation of high-temperature resistance including heat-resistant mechanism and process, in conjunction with high-temperature packaging design, enable the sensor to be used in environment up to 400 °C. The packaged sensor is calibrated over a range of ~65 Pa and then used to examine the development of the transient flow of the scramjet ignition process (Mach 2 airflow, stagnation pressure, and a temperature of 0.8 MPa and 950 K, respectively). The results show that the sensor is able to detect the transient flow conditions of the scramjet ignition process including shock impact, flow correction, steady state, and hydrogen off.

Two-dimensional imaging of gas-to-particle transition in flames by laser-induced nanoplasmas

Two-dimensional imaging of gas/particle phase transition of metal oxides in their native high-temperature flow conditions, using laser-driven localized nanoplasmas, was obtained by utilizing the gap between the excitation energies of the gas and particle phases such that only the Ti atoms in the particle phase were selectively excited without detectable Bremsstrahlung background. These in situ images of the particle phase Ti distribution allow the quantitative visualization of the transition of the gas precursors to the nanoparticle phase across the flame sheet as well as diffusion of the particle concentration in the post-flame zone.

Hydrodynamic analogies of the phenomena of ignition and extinction

The problem of determining the steady-state dissipative heating of a Newtonian liquid moving in a round tube of finite length, taking account of the dependence of the viscosity on the temperature, is formulated. The possibility of a jumpwise transition from low-temperature flow conditions with small mass flow rates to high-temperature flow conditions with large mass flow rates, and the reverse with a gradual change in the pressure drop, is established. This phenomenon is brought about by hydrodynamic thermal ignition and extinction; an analytical description of it is given.