Christian Jungreuthmayer

A Detailed Heat and Fluid Flow Analysis of an Internal Permanent Magnet Synchronous Machine by Means of Computational Fluid Dynamics

This paper presents a comprehensive computational fluid dynamics (CFD) model of a radial flux permanent magnet synchronous machine with interior magnets. In the CFD model, the water jacket cooling and a simplified model of the topology of the distributed stator winding are considered. The heat sources of the CFD model are determined from a finite-element analysis of the machine. The numerically determined temperature distributions of the machine are compared with measurement results from sensors located both in the stator and rotor. The particular focus of this paper is the analysis of the temperatures and the heat flow in the air gap and from the stator winding heads and the rotor to the inner air. Different operating conditions and two particular rotor designs with different inner air flow configurations are investigated. The potential of improving the thermal utilization of a rotor design with fan blades attached to the mounting plates of the rotor is shown.

An innovative parametrization method for a thermal equivalent circuit model of an interior permanent magnet synchronous machine

In this paper an accurate and fast thermal equivalent circuit (TEC) model of an interior permanent magnet synchronous machine (IPMSM) is presented. This model is capable of simulating transient thermal effects. The key parameters of the presented model are the heat transfer coefficients which consider heat transfer from the solid to the fluid regions, and vice versa. An innovative parametrization method is introduced to determine these coefficients: First, the heat flows between adjacent regions are calculated by utilizing a 3D computational fluid dynamics (CFD) simulation. Second, the heat transfer coefficients of the TEC model are determined by minimizing an objective function which takes the heat flow deviation between the TEC model and the CFD model into account. The TEC model parametrized this way can be used to predict the thermal behavior of a permanent magnet machine drive under varying speed and torque conditions. The validity of the TEC model is verified by means of measurement results. For this purpose a prototype of the investigated IPMSM is equipped with temperature sensors in the stator, rotor, and cooling circuit, respectively.

Rapid liposome quality assessment using a lab-on-a-chip

Although liposomes have many outstanding features such as biocompatibility, biodegradability, low toxicity and structural diversity, and are successfully applied in many areas of chemistry and biotechnology, a lack of characterization standards and quality control tools are still inhibiting the translation of liposome technology into clinical routine. The greatest obstacle to clinical scale commercialization is the inability to ensure liposome formulation stability because small size variations or altered surface chemistries can significantly influence in vivo distribution and excretion kinetics that could in turn lead to unpredictable therapy outcomes. To enhance the product development process we have developed a microfluidic biochip containing embedded dielectric microsensors capable of providing quantitative results on formulation composition and stability based on the monitoring of the unique electric properties of liposomes. Computational fluid dynamic (CFD) simulations confirmed that microfluidics offer reproducible and well-defined measurement conditions where a moving liposome suspension within a microchannel behaves like a bulk material. Results of this study demonstrate the ability of microfluidics, in combination with dielectric spectroscopy and multivariate data analysis methods, to identify nine different liposomes. We also show that various liposome modifications such as membrane-bound surface proteins, lipid bilayer soluble drugs, as well as protein and dye encapsulations, can be detected in the absence of any labels or indicators. Since shelf-life stability of a liposome formulation is regarded of prime importance for regulatory approval and clinical application, we further provide a possible practical application of the developed liposome analysis platform as a high-throughput tool for industrial quality insurance purposes.

Heat and fluid flow analysis of an internal permanent magnet synchronous machine by means of computational fluid dynamics

This paper presents a comprehensive computational fluid (CFD) model of a radial flux permanent magnet synchronous machine with interior magnets. In the CFD model the water jacket cooling and a simplified model of the topology of the distributed stator winding are considered. The heat sources of the CFD model are determined from a finite element analysis of the machine. The numerically determined temperature distributions of the machine are compared with measurement results from sensors located both in the stator and rotor. The particular focus of this paper is the analysis of the temperatures and the heat flow in the air gap and from the stator winding head and the rotor to the inner air.

Designing Optimized Production Hosts by Metabolic Modeling

Many of the complex and expensive production steps in the chemical industry are readily available in living cells. In order to overcome the metabolic limits of these cells, the optimal genetic intervention strategies can be computed by the use of metabolic modeling. Elementary flux mode analysis (EFMA) is an ideal tool for this task, as it does not require defining a cellular objective function. We present two EFMA-based methods to optimize production hosts: (1) the standard approach that can only be used for small and medium scale metabolic networks and (2) the advanced dual system approach that can be utilized to directly compute intervention strategies in a genome-scale metabolic model.