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Full-Text Articles in Mechanical Engineering
Rarefication Effects On Jet Impingement Loads, Shiying Cai, Chunpei Cai, Kai Zhang, Jun Li
Rarefication Effects On Jet Impingement Loads, Shiying Cai, Chunpei Cai, Kai Zhang, Jun Li
Michigan Tech Publications
Rarefication effects on jet impingement loads are studied by comparing recent new formulas at the collisionless flow limit and numerical simulations. The jet exit size is finite, and can be either planar or round. In the simulations, the jets have different degrees of rarefication, with a Knudsen (Kn) number ranging from 0 to infinity; i.e., the jet flows can be continuum, collisional, or collisionless. The comparison results indicate that (1) the new surface load formulas are accurate at the collisionless flow limit; (2) in general, the formulas offer upper limits for the peak loads; (3) however, it is improper to …
An Improved Electron Pre-Sheath Model For Tss-1r Current Enhancement Computations, Chunpei Cai
An Improved Electron Pre-Sheath Model For Tss-1r Current Enhancement Computations, Chunpei Cai
Michigan Tech Publications
This report presents improvements of investigations on the Tethered Satellite System (TSS)-1R electron current enhancement due to magnetic limited collections. New analytical expressions are obtained for the potential and temperature changes across the pre-sheath. The mathematical treatments in this work are more rigorous than one past approach. More experimental measurements collected in the ionosphere during the TSS-1R mission are adopted for validations. The relations developed in this work offer two bounding curves for these data points quite successfully; the average of these two curves is close to the curve-fitting results for the measurements; and an average of 2.95 times larger …
The Influence Of Bmss On The Characterization And Modeling Of Series And Parallel Li-Ion Packs, Sandra Castano-Solis, Daniel Serrano-Jimenez, Lucia Gauchia, Javier Sanz
The Influence Of Bmss On The Characterization And Modeling Of Series And Parallel Li-Ion Packs, Sandra Castano-Solis, Daniel Serrano-Jimenez, Lucia Gauchia, Javier Sanz
Michigan Tech Publications
This work analyzes the effects of a BMS (battery management system) on the characterization and modeling of series and parallel connections of Li-ion cell packs. The Li-ion pack studied consists of four series modules connected in parallel. This pack has been characterized by means of charge, discharge and frequency tests. As a result of these tests, series and parallel influence on battery parameters have been determined. A model considering the effects of a BMS is established and compared with a model based on a single-cell approach. Experimental validations show that the single cell based approach gives poor results in comparison …
A New Gaskinetic Model To Analyze Background Flow Effects On Weak Gaseous Jet Flows From Electric Propulsion Devices, Chunpei Cai
A New Gaskinetic Model To Analyze Background Flow Effects On Weak Gaseous Jet Flows From Electric Propulsion Devices, Chunpei Cai
Michigan Tech Publications
Recent work on studying rarefied background and jet flow interactions is reported. A new gaskinetic method is developed to investigate two closely related problems. The first problem is how a collisionless background flow can affect a highly rarefied jet flow. The rarefied jet and background flow conditions are assumed available and described with seven parameters. Gaskinetic theories are applied and formulas are obtained for the mixture properties. Simulations are performed to validate these expressions, and excellent agreement is obtained. The second problem is to recover the collisionless background and jet flow parameters with limited measurements. A group of linearized equations …