To increase the efficiency of the engine is one of the biggest challenges for heavy vehicles. One possible method is the Rankine based Waste Heat Recovery. Crucial for Rankine based Waste Heat Recovery is to model the temperature and the state of the working fluid. If the state of the working fluid is not determined, not only the efficiency of the system could be decreased, the components of thesystem might be damaged.A Simulink model based on the physical components in a system developed by Scania is proposed. The model for the complete system is validated against a reference model developed by Scania, and the component models are further validated against measurement data. The purpose of the model is to enable model based control, which is not possible with the reference model. The main focus on the thesis is to model the evaporation and condensation to determine state and temperature of the working fluid. The developed model is compared to a reference model with little differences for while stationary operating for both the components and the complete system. The developed model also follows the behavior from measurement data. The thesis shows that two phase modeling in Simulink is possible with models based on the physical components.

This thesis work has been performed at the department of diagnosis and dependability at Volvo Car Company, Torslanda. The background of this project is based on interest in ascertaining how different factors possibly can affect a diagnosis method, which has been developed to find leaks in the fuel tank and evaporation system. According to the OBD II requirements leaks with an orifice diameter larger or equal to 0,5 mm, must be detected. The idea of the diagnosis method is to create an over pressure in the system with an air-pump. The current through the pump is measured and correlates to the power consumed by the pump. As the power is a function of the pressure difference over the pump, the pump current correlates to the pressure in the tank. Thus, the pump current can be used as a measure of the impenetrability. Changes in the system pressure, not caused by the pump, are accordingly disturbances to the method. The object of this work was to develop mathematical models, describing the lapse where the system is pressurized by the pump under the influence of different physical factors. The model is for instance considering variations in temperature and height, flow resistance in lines and valves, component characteristics, fuel evaporation, leaks etc. Furthermore the pump current is treated by the diagnosis evaluation algorithm with purpose to judge whether there is a leak in the system. The model has been implemented in Matlab/Simulink and it can consequently be used in dynamic simulations according to the over pressure leakage detection concept. Numerical experiments can be done in purpose to examine how changes in environmental conditions or component characteristics will affect the diagnosis method. Good agreement has been found between measurements and simulated results. The diagnosis function produces correct decisions under different conditions with disparity in leak sizes, additionally confirming the reliability of the model.

The convective mass transfer coefficient is determined for evaporation in a horizontal rectangular duct, which forms the test section of the transient moisture transfer (TMT) facility. In the test facility, a short pan is situated in the lower panel of the duct where a hydrodynamically fully developed laminar or turbulent airflow passes over the surface of the water. The measured convective mass transfer coefficients have uncertainties that are typically less than ±10% and are presented for Reynolds numbers (ReD) between 560 and 8,100, Rayleigh numbers (RaD) between 6,100 and 82,500, inverse Graetz numbers (Gz) between 0.003 and 0.037, and operating conditions factors (H*) between -3.6 and -1.4. The measured convective mass transfer coefficients are found to increase as ReD, RaD, Gz and H* increase and these effects are included in the Sherwood number (ShD) correlations presented in this thesis, which summarize the experimental data.<p> An analogy between heat and mass transfer is developed to determine the convective heat transfer coefficients from the experimentally determined ShD correlations. The convective heat transfer coefficient is found to be a function of ShD and the ratio between heat and moisture transfer potentials (S*) between the surface of the water and the airflow in the experiment. The analogy is used in the development of a new method that converts a pure heat transfer NuD (i.e., heat transfer with no mass transfer) and a pure mass transfer ShD (i.e., mass transfer with no heat transfer) into NuD and ShD that are for simultaneous heat and mass transfer. The method is used to convert a pure heat transfer NuD from the literature into the NuD and ShD numbers measured in this thesis. The results of the new method agree within experimental uncertainty bounds, while the results of the traditional method do not, indicating that the new method is more applicable than the traditional analogy between heat and mass transfer during simultaneous heat and mass transfer.<p>A numerical model is developed that simulates convective heat and mass transfer for a vapor permeable Tyvek® membrane placed between an airflow and liquid water. The boundary conditions imposed on the surfaces of the membrane within the model are typical of the conditions that are present within the TMT facility. The convective heat and mass transfer coefficients measured in this thesis are applied in the model to determine the heat and moisture transfer through the membrane. The numerical results show that the membrane responds very quickly to a step change in temperature and relative humidity of the air stream. Since the transients occur over a short period of time (less than 1 minute), it is feasible to use a steady-state model to determine the heat and mass transfer rates through the material for HVAC applications.<p>The TMT facility is also used to measure the heat and moisture transfer through a vapor permeable Tyvek® membrane. The membrane is in contact with a water surface on its underside and air is passed over its top surface with convective boundary conditions. The experimental data are used to verify the numerically determined moisture transfer rate through the Tyvek® membrane. The numerical model is able to determine the mass transfer rates for a range of testing conditions within ±26% of the experimental data. The differences between the experiment and the model could be due to a slightly different mass transfer coefficient for flow over Tyvek® than for flow over a free water surface.

No description available.

This research describes an investigation on the fabrication of CuInSe2-based thin-film solar cells with the device structure of Al/ZnO:Al/ZnO/CdS/CIS/Mo/SLG at the substrate temperature of 450oC, which is at least 100oC below the temperature currently used for depositing CIS thin films. A great advantage for the low temperature process is that the polymer material can be used as substrate and it is feasible to make lightweight and flexible thin-film solar cells. In this work, we used a co-evaporation technique with an introduction of Sb during the film deposition process to modify the film growth mechanisms and produce the CIS film with compact grain structure and smooth surface morphology. In most cases, there was only tiny amount of Sb existed in the film as a p-type dopant. In some cases, second phases of Sb compounds could be detected in the film as the Sb flux was kept too high during the film deposition stage. The I-V characteristics measured under the AM1.5 condition for the solar cell using a CIS:Sb film as the absorber showed that the open circuit voltage (Voc) was 0.364 V, short circuit current (Jsc) was 48.16 mA/cm2, fill factor (FF) was 44.5%, and energy conversion efficiency (£b) was 8%. The device with the same layer structure except the use of CIS film prepared without the addition of Sb and at a higher substrate temperature of 550oC had a comparable device performance but a slightly lower efficiency, i.e. Voc=0.325 V, Jsc=48.54 mA/cm2, FF=45.1%, £b=7.4%. It is clear that a lower temperature process using Sb to modify the growth process can be successful to obtain a device quality CIS layer. In addition, a CIGS thin-film solar cell was also fabricated and its device properties were Voc=0.392 V, Jsc=37.28 mA/cm2, FF=46.2%, and £b=7.0%. We see that the addition of Ga to increase the bandgap do increase the Voc and decrease the Jsc. However, a low efficiency of this cell indicates that further improvement in fill factor of the cell is a necessary.

ABC type amphiphilic triblock copolymers, polyethylene-b-poly(ethylene oxide)-b-poly (£`-caprolactone) (PE-b-PEO-b-PCL), were synthesized through ring-opening polymerization. We have successfully synthesized hierarchical mesoporous silicas using a simple evaporation-induced self-assembly (EISA) strategy. Two blocks of hydrophobic segment (PE and PCL) in the triblock copolymer (PE-b-PEO-b-PCL) involved in two-type mesepores after calcinations. We recognized the PE segment attributed to face centered cubic (f. c. c.) morphology (spherical pore) and the PCL segment attributed to tetragonal cylinder structure (cylinder pore) by small angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and specific surface area & pore size distribution analyzer (BET), respectively. We also investigated the effect on pore size and morphology with changing the molecular weight of PCL and the ratios of TEOS/template/HCl. We also synthesized the mesoporous phenolic resin by triblock copolymer poly(ethylene oxide)-b-poly(£`-caprolactone)-b-poly(L-lactide) (PEO-b-PCL-b-PLLA). After curing and calcinations, we also explored the morphology and pore size distribution of mesoporous phenolic by SAXS, TEM, BET. Because of the sequence of hydrophobic segment PCL and PLLA lay in the same side, so we could only observe hexagonal cylinder structure and one pore size.

The study focus on low temperature process with doping antimony to refine the quality of the CI(G)S thin film, and doping gallium to increase energy band gap in two-stage co-evaporation process. Furthermore, we discuss about the variety of crystal structure, and recognize the value of energy band gap in transmission spectra. It has been achieved to increase the energy band gap of material with doping gallium. Recognizing the shift of XRD pattern and research result from papers, I estimate the content ratio of gallium in ¢»A atoms is 0.28~0.29, near my establishment ratio 0.3. By tuning the molecular beam flux of antimony effusion cell from 1.1¡Ñ1013 atoms/cm2second to 2.2¡Ñ1014 atoms/cm2second , to find out the property content of antimony involving of co-evaporation to optimize the quality of the CI(G)S polycrystalline thin film. We just observed that the thin film with antimony involving make effect of smoother and denser surface morphology. In our study, we also try discontinue supplying the antimony vapor to reduce the amount of antimony which involves the reaction process, and make low content of antimony leaved in the CI(G)S thin film. Here, We found out a special effect of the grain- growth of the CI(G)S thin film supplying antimony continually or not in the process. It should be strong (112) prefer orientation when we deposit the thin film using SLG substrate. However, we found out that antimony enhance the (220/204) .

Magnesium (Mg) thin films with various thicknesses ranging from 50 to 1000 nm capped with nominally 20 nm Palladium (Pd) were prepared by a thermal evaporation unit. A total of 25 glass substrates were used in each experiment. The unit had a rotatable macro shutter, rectangular in shape, rotation axes opposite to the Mg source, which allowed controlled exposure of the substrates. Thin films of 50, 100, 150, 200, 300, 400, 500, 600, 800 nm and 1000 nm were produced in a single experiment. Hydrogenation and dehydrogenation of the films were examined using a gas loading chamber which allowed in-situ resistance measurement. Samples were hydrogenated isochronally up to 453 K with a heating rate of 1.5 K/min. Samples cooled to room temperature were subjected to dehydrogenation test. The chamber was taken under vacuum (~10-2 mbar) and the sample was heated up to 453 K at a rate of 1.5 K/min. The results showed that the hydrogenation and dehydrogenation temperatures correlate with the film thickness, thinner films reacting with hydrogen at low temperatures. While 200 nm thin film hydrogenated at 420 K and desorbed it at 423 K, 50 nm thin film hydrogenated at room temperature and desorbed it at 405 K. Thicker films needed higher temperatures to react with hydrogen. It is concluded that films thinner than 200 nm react fully with hydrogen / while a considerable portion of the thicker films remain unreacted. Significance of this is discussed with reference to the design of hydrogen storage systems based on thin films or nanoparticles.

As the demand for high performance small electronic devices has increased, heat removal from these devices for space use is approaching critical limits. A heat pipe is a promising device to enhance the heat removal performance due to the phase change phenomena for space thermal management system. Even though a heat pipe has a big potential to remove the thermal energy from a high heat flux source, the heat removal performance of heat pipes cannot be predicted well since the first principle of evaporation has not been established. The purpose of this study is to establish a method to apply the evaporation model based on the statistical rate theory for engineering application including vapor-liquid-structure intermolecular effect. The evaporation model is applied to the heat pipe performance analysis through a pressure balance and an energy balance in the loop heat pipe.

Thesis (Ph. D.)--Institute of Paper Chemistry, 1961. / Includes bibliographical references (p. 161-162).