An experimental study is presented for the mixing of one-and dual-line heated jets injected at 60° angle with x-axis into a cold crossflow in a rectangular channel.Measurements of the mean temperature,velocity,an...An experimental study is presented for the mixing of one-and dual-line heated jets injected at 60° angle with x-axis into a cold crossflow in a rectangular channel.Measurements of the mean temperature,velocity,and turbulence intensity together with the flow visualization were performed.Self-similar forms for the dimensionless vertical temperature profiles were found.Parametric variations characterizing the mixing processes of the temperature and velocity fields were examined and correlated in terms of the momentum flux ratio and downstream distance.Results show that both the thermal and velocity penetration depths increase with increasing momentum flux ratio and downstream distance.The turbulence intensity is strong within the region of jet half-width,and the maximum value occurs at a point close to the jet velocity trajectory.展开更多
The mass flow rate measurement using a critical nozzle shows the validity of the inviscid theory, indicating that the discharge coefficient increases and approaches unity as the Reynolds number increases under the ide...The mass flow rate measurement using a critical nozzle shows the validity of the inviscid theory, indicating that the discharge coefficient increases and approaches unity as the Reynolds number increases under the ideal gas law However, when the critical nozzle measures the mass flow rate of a real gas such as hydrogen at a pressure of hundreds bar, the discharge coefficient exceeds unity, and the real gas effects should be taken into account. The present study aims at investigating the flow features of the critical nozzle using high-pressured hydrogen gas. The axisymmetric, compressible Navier-Stokes computation is employed to simulate the critical nozzle flow, and a fully implicit finite volume method is used to discretize the governing equation system. The real gas effects are simulated to consider the intermolecular forces, which account for the possibility of liquefying hydrogen gas. The computational results are compared with past experimental data. It has been found that the coefficient of discharge for real gas can be corrected properly below unity adopting the real gas assumption.展开更多
基金Partial support of this work by the Science and Technology Coordination Council in Defence in Taiwan under Grants CS 79-0210-D110-03
文摘An experimental study is presented for the mixing of one-and dual-line heated jets injected at 60° angle with x-axis into a cold crossflow in a rectangular channel.Measurements of the mean temperature,velocity,and turbulence intensity together with the flow visualization were performed.Self-similar forms for the dimensionless vertical temperature profiles were found.Parametric variations characterizing the mixing processes of the temperature and velocity fields were examined and correlated in terms of the momentum flux ratio and downstream distance.Results show that both the thermal and velocity penetration depths increase with increasing momentum flux ratio and downstream distance.The turbulence intensity is strong within the region of jet half-width,and the maximum value occurs at a point close to the jet velocity trajectory.
文摘The mass flow rate measurement using a critical nozzle shows the validity of the inviscid theory, indicating that the discharge coefficient increases and approaches unity as the Reynolds number increases under the ideal gas law However, when the critical nozzle measures the mass flow rate of a real gas such as hydrogen at a pressure of hundreds bar, the discharge coefficient exceeds unity, and the real gas effects should be taken into account. The present study aims at investigating the flow features of the critical nozzle using high-pressured hydrogen gas. The axisymmetric, compressible Navier-Stokes computation is employed to simulate the critical nozzle flow, and a fully implicit finite volume method is used to discretize the governing equation system. The real gas effects are simulated to consider the intermolecular forces, which account for the possibility of liquefying hydrogen gas. The computational results are compared with past experimental data. It has been found that the coefficient of discharge for real gas can be corrected properly below unity adopting the real gas assumption.
