Diffuser (thermodynamics)

About: Diffuser (thermodynamics) is a research topic. Over the lifetime, 6731 publications have been published within this topic receiving 54738 citations.

Investigation of the Prediction of Losses in Radial Vaneless Diffusers

Abstract: The non-dimensional width B and the inlet flow angle αi are the important parameters influencing the losses and the stability of radial vaneless diffusers. Their effects on diffuser losses are analyzed in this paper. The portions of the various flow losses change with the variation of non-dimensional width parameter B and flow angle αi. In a diffuser with small width B, the loss is primarily due to wall friction loss. In a diffuser with large B, the wall friction loss becomes a small part of the total loss, especially when αi is large. Comparison with experimental data shows that it is better to calculate the performance parameters of radial vaneless diffusers by using Dou’s method than by Senoo’s method in the design of centrifugal compressors. Senoo’s method is found to be only suitable for the conditions of small B values because it calculates simply the wall friction loss and the secondary flow loss and neglects diffusion loss.Copyright © 1991 by ASME

Heat treat furnace with multi-bar high convective gas quench

Abstract: An improved cooling arrangement is disclosed for an industrial heat treat furnace. The furnace includes a closed end cylindrical heat treat chamber in which a plenum plate is suspended adjacent the rear end thereof. The plenum plate has a central underpressure opening and a fan between the rearward end of the furnace and the plate develops a wind mass which circulates into the furnace chamber and is drawn back into the fan through the plates central underpressure opening. Between the plenum plate and the furnace rearward end is positioned a first fixed fan diffuser followed by a second fixed fan diffuser. The first fan diffuser permits wind mass flow therethrough when the fan is rotated in a first direction but not in a second direction and similarly the second fan diffuser permits wind mass flow therethrough when the fan is rotated in a second direction but not in a first direction. A cooling coil arrangement is placed adjacent the second fixed fan diffuser to permit accurate control of the cooling of the work by simply cycling fan rotation direction from clockwise to counterclockwise.

Performance of Tee Diffusers in Shallow Water with Crossflow

Abstract: The dilution and plume trajectory of the tee diffuser has been investigated via the collection of experimental data for a wide range of ambient current conditions. A new dilution equation in which the stagnation effect between ambient current and diffuser discharge is assumed to be a function of the ratio of the ambient momentum to the discharge momentum, mr, is proposed modifying the conventional theory of Adams that significantly underpredicts mixing for large mr. A simple equation for the plume trajectory including the dependency of the momentum ratio is also derived by dimensional analysis. Experimental results on the near field dilution show that when mr 1 it increases with increasing mr, and approaches the stagnant water dilution for very large values of mr. The equation is applied to aid the preliminary design of a diffuser discharging heated water from a power station in Korea.

Numerical analysis and performance experiment of electric submersible pump with different diffuser vanes number

Abstract: Space diffuser is one of the most critical flow components in electric submersible pumps; its hydraulic design has the significant effects on the pump performance. In this paper, a typical electric submersible pump was chosen as the research object to study the influence of space diffuser vanes number, by means of numerical simulation and experimental test methods. Based on the same curve profile and same impeller, the diffuser vanes number was adjusted to three different schemes of 6, 7, and 8. Calculation domain was created based on single-stage pump model, and meshed by the high density of structured grids associating with grid independence analysis. The numerical simulations under multi-conditions were performed based on SST k-ω turbulence model and standard wall function. Through the comparisons of predicted pump performance, we found that the pump head is increasing slightly with the increase of vanes number under part-loading conditions. However, excessive vanes occupy more passage area, which leads to blockings and more hydraulic losses under over-loading conditions. The diffuser scheme with seven vanes matches the impeller very well with less hydraulic losses. The test results prove that this scheme has an excellent pump performance, both the single-stage head and efficiency are higher than the Chinese national standard.