Sparsity-enhanced optimization for ejector performance prediction

Abstract

Within a model of the ejector performance prediction, the influence of ejector component efficiencies is critical in the prediction accuracy of the model. In this paper, a unified method is developed based on sparsity-enhanced optimization to determine correlation equations of ejector component efficiencies in order to improve the prediction accuracy of the ejector performance. An ensemble algorithm that combines simulated annealing and gradient descent algorithm is proposed to obtain its global solution for the proposed optimization problem. The ejector performance prediction of a 1-D model in the literature is used as an example to illustrate and validate the proposed method. Tests results reveal that the maximum and average absolute errors for the ejector performance prediction are reduced much more when compared with existing results under the same experimental condition. Furthermore, the results indicate that the ratio of geometric parameters to operating parameters is a key factor affecting the ejector performance.

Performance Predictions of Dry and Wet Vapors Ejectors Over Entire Operational Range

“…The other efficiencies are optimized based on the experimental data and the methods in [18]. They are: The theoretical results of ejector performance are compared with the experimental data as shown in Table 3.…”

“…Hence, the efficiencies η m and η d are taken as constant since entrainment ratio and critical condensing pressure are not sensitive to them. The other efficiencies were determined by sparsity-enhanced optimization [18] based on the foregoing experiment. For the ejector model at breakdown point, three component efficiencies are used, η p and η d are taken as those in the critical point model due to the same choking phenomenon and compression process, respectively, and η mb will be expressed as correlation equations as breakdown condensing pressure is sensitive to it.…”

“…The main objective of this paper is hence to propose a novel model for both dry and wet vapor ejectors over the entire operational range. To obtain high accuracy, the following strategies were adopted: (1) developing the critical and breakdown points models based on constant-pressure mixing and constant-pressure disturbing, and integrating them with linear characteristic equations of ejector to form the model; (2) introducing real gas property and the equations of sound speed with high evaluation accuracy into the models; (3) adopting the analysis method of the effect of change (EOC) of the efficiencies [17] and the sparsity-enhanced optimization method [18] to identify and determine the correlation equations of ejector components efficiencies. Then, the model was employed to analyze the influences on the ejector performance induced by superheating the primary flow before it enters the ejector.…”

Combinatorial Analysis Methodologies for Accelerated Research: The Case of Chalcogenide Thin‐Film Photovoltaic Technologies

“…However, despite these advantages, the higher degree of control of the compositional gradient that can be achieved with PVD techniques makes them the preferred strategy for synthesizing thin‐film combinatorial samples. [ 64 ] Focusing on chalcogenide‐based solar cells, synthesized by combinatorial methods, there exist several works reporting the employment of sputtering, [ 69–79 ] a lower amount of articles report the use of thermal evaporation [ 80–83 ] and CBD, [ 66,84,85 ] and there are also reports describing the use of spray coating, [ 68,86 ] PLD, [ 87 ] and CVD. [ 88 ] The experimental setups required for adapting both PVD and CM techniques for the deposition of combinatorial samples are discussed in a review by McGinn.…”

The Ejection Efficiency of Cooling Charge Air and Its Experimental Evaluation

“…Особенностью системы эжекционного охлаждения наддувочного воздуха является снижение затрат энергии на создание воздушного потока через охладитель и потерь мощности двигателя на функционирование системы газообмена [8,9] использованием газового эжектора.…”