Polymer electrolyte membrane (PEM) fuel cells are highly efficient energy converters and provide electrical energy, cathode exhaust gas with low oxygen content, water and heat. Recently, fuel cells have been investigated for the use on aircraft where they have the potential of replacing the auxiliary power units (APU) that are currently used for generating electrical power during ground operati...

Preface In the scope of my studies at the Technical University of Denmark (DTU) in the Engineering Acoustics master program, I have done my final project about modelling distortion in condenser microphones. This subject was originally proposed by Brüel & Kjaer Sound & Vibration Measurement A/S (B&K) under the title Distortion process in condenser microphones. In February 2009 I have started my ...

Microchannel heat exchangers (MCHX) are being increasingly applied in heat pumps because of their compactness, significant charge reduction, lower refrigerant pressure drop and lower air-side fan power consumption compared to traditional round tube-plate fin (RTPF) heat exchangers. Using a microchannel condenser as well as evaporator in a heat pump system also offers significant potential for c...

A numerical simulation of a liquid overfeed system working with pure refrigerants in steady state conditions has been performed. The global algorithm is based on the sequential resolution of the different elements of the system (compressor, evaporator, condenser, ... ). For each element, a simplified mathematical model based on global balances of mass, momentum and energy is used. For the evapo...

using the electrostatic capacity of a condenser, the existence of a distance function on a finsler space is discussed. this distance function divides finsler spaces into the two classes, denoted here by i and ii. the topology generated by this distance on the finsler spaces of class ii coincides with its intrinsic topology. this work provides a natural extension of mathematical analysis tools n...

Blair's recent theory of excitation is analysed with the following conclusions: 1. The theory is inapplicable to currents of long duration; i.e., slowly increasing currents and the opening excitation. 2. The theory is a modification of the condenser theory of excitation but the modification is to be rejected on three grounds: (a) The modification has no obvious physical significance. (b) It doe...

The corona discharge in the steam is investigated theoretically and experimentally in means of implementation with the steam condenser for the improved phase-change rate. The considered phenomena include the nucleation of water vapor on mobile charge carriers, the electrohydrodynamic vapor flow toward the condenser wall and the thermodynamics of the charged micro-droplet. The average size of mi...