Щоб переглянути інші типи публікацій з цієї теми, перейдіть за посиланням: Cooling.
Дисертації з теми "Cooling"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "Cooling".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
1
Katta, Kiran Kumar. "Phase change cooling applications engine cooling /." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2008. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
Повний текст джерела
2
Chen, Ruiping. "Laser cooling of atoms for ultracold cooling." Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.479242.
Повний текст джерела
3
Srikanth, Sai Aswin. "Use of Electrical Coolant Pumps in Scania’s Cooling System." Thesis, KTH, Maskinkonstruktion (Avd.), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-259681.
Повний текст джерелаАнотація:
The automotive industry is currently traversing through the electrification wave. Numerous manufacturers are directing focus to electrify their lineup and reduce emissions. In the frontier of heavy duty diesel trucks, electrification of auxiliary units remains an unexplored potential. An optimized cooling system functioning in sync with a controllable electric coolant pump attempts to reduce parasitic losses and emissions. The cooling flow requirements in challenging conditions may also be fulfilled. Although electric coolant pumps are found increasingly in passenger cars, the implication of independently operating them in a heavy duty diesel truck is an important objective to be explored. The purpose of this project is to generate different cooling system layouts coupled with electrical coolant pumps. The performance of these layouts is compared with the volume flows in a standard cooling system. Refined layouts which fulfill the cooling system requirements are chosen for verification. 1-D Simulation is used to correlate and verify the trends of the test rig data. The results show an adequate gain in the total volume flow across distinct layouts with the electric coolant pumps. However, numerous challenges are required to be overcome.Bilindustrin befinner sig mitt i en våg av elektrifiering. Flertalet tillverkare fokuserar på att elektrifiera sitt produktutbud och att minska utsläppen. Inom forskningen kring tunga transporter med dieseldrivna lastbilar, är elektrifiering av kylsystemet ett outforskat område. Ett optimerat kylsystem som är reglerbart med en elektrisk kylvätskepump skulle potentiellt kunna minska energiförluster och utsläpp. Kravet på flödet av kylvätska vid utmanande driftsfall skulle också kunna bli bättre uppfyllda än för dagens system. Trots att det blir allt vanligare att personbilar har elektriska kylvätskepumpar, så har det inte utforskats vad det innebär att ha reglerbara elektriska kylvätskepumpar i dieseldriva lastbilar. Därför är detta ett viktigt område att utforska. Målet med detta projekt är att skapa olika kylsystemskoncept, där den elektriska kylvätskepumpen är en systemkomponent. Prestandan hos dessa principlösningar jämförs sedan med volymflödet i ett standard kylvätskesystem. Koncept som uppfyller kraven för kylvätskesystemet kommer att bli utvalda för vidare verifiering. 1-D simuleringar används för att hitta samband och verifiera mot trenderna som hittas i resultat från en testrigg. Resultaten visar en förbättring i det totala volymflödet för flera av lösningarna, som har en elektrisk kylvätskepump. Men det finns fortfarande flera utmaningar som behöver övervinnas.
4
Graça, Guilherme Carrilho da 1972. "Ventilative cooling." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/66785.
Повний текст джерелаАнотація:
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Architecture, 1999.Includes bibliographical references (p. 131-134).
This thesis evaluates the performance of daytime and nighttime passive ventilation cooling strategies for Beijing, Shanghai and Tokyo. A new simulation method for cross-ventilated wind driven airflow is presented . This method decouples the airflow model from the thermal model allowing for fast real weather simulation of the building thermal performance. The simulation is performed on a six-story, isolated, suburban apartment building, considered to be typical of the three cities. The performance of the two natural ventilation strategies on this building is compared . The impact on the performance of different types of construction is assessed for the night cooling ventilation strategy. The results show that night cooling is superior to daytime ventilative cooling in the three cities. Night cooling can successfully replace air conditioning systems for a significant part of the cooling season in Beijing and Tokyo. For Shanghai, neither of the two passive ventilation systems can be considered successful. In both Beijing and Tokyo the application of night cooling may cause condensation in partitions. The use of heavyweight partitions does not show a noticeable improvement over normal construction (using 10cm concrete partitions) . On the other hand, the lightweight case shows a noticeable degradation in system performance. Therefore, the normal structural system is the best option. The use of carpet has a very negative impact on night cooling performance, and is therefore not advised.
by Guilherme Carrilho da Graça.
S.M.
5
Rizvani, Lejla. "Cooling Oasis." Thesis, KTH, Arkitektur, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298809.
Повний текст джерелаАнотація:
The urban heat island, UHI, is a phenomenon that occurs in all cities. This phenomenon is an effect of us humans and the environments we have built. What happens in cities are that they re-emit the suns heat and other energies trapping them in this heat island. The re-emitting happens through the pavement of the city, lack of greenery, roads and how the city is built and its geometry. Cities with skycrapers and of high density see a greater impact of the urban heat island where the wind flow is reduced and more heat is trapped and stored. The UHI is worst experienced in places with a very hot climate, such as the arid desert climate with extreme temperatures year round, like in the UAE and Dubai. It is vital to tackle the UHI effect problem, because it puts people at danger. Many lives are shed each year due to heat strokes, that can be reduced if we take this problem into consideration when we design our cities. The UHI effect can be reduced by simple yet effective steps.
6
Fletcher, Daniel Alden. "Internal cooling of turbine blades : the matrix cooling method." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360259.
Повний текст джерела
7
VILAFRANCA, MANGUÁN ANA. "Convesion of industrial compression cooling to absorption cooling in an integrated district heating and cooling system." Thesis, University of Gävle, University of Gävle, Department of Technology and Built Environment, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-4145.
Повний текст джерелаАнотація:
Astra Zeneca plant in Gärtuna has many compression cooling machines for comfort that consume about 11.7 GWh of electricity per year. Many of the cooling machines are old; due to the increase of production of the plant, cooling capacity was limited and new machines have been built. Now, the cooling capacity is over-sized. Söderenergi is the district heating plant that supplies heating to Astra Zeneca plant. Due to the strict environmental policy in the energy plant, last year, a bio-fuelled CHP plant was built. It is awarded with the electricity certificate system.
The study investigates the possibility for converting some of the compression cooling to absorption cooling and then analyzes the effects of the district heating system through MODEST optimizations. The effects of the analysis are studied in a system composed by the district heating system in Södertälje and cooling system in Astra Zeneca. In the current system the district heating production is from boiler and compression system supplies cooling to Astra Zeneca. The future system includes a CHP plant for the heating production, and compression system is converted to absorption system in Astra Zeneca. Four effects are analyzed in the system: optimal distribution of the district heating production with the plants available, saving fuel, environmental impact and total cost. The environmental impact has been analyzed considering the marginal electricity from coal condensing plants. The total cost is divided in two parts: production cost, in which district heating cost, purchase of electricity and Emissions Trading cost are included, and investment costs. The progressive changes are introduced in the system as four different scenarios.
The introduction of the absorption machines in the system with the current district heating production increases the total cost due to the low electricity price in Sweden. The introduction of the CHP plant in the district heating production supposes a profit of the production cost with compression system due to the high income of the electricity produced that is sold to the grid; it profit increases when compression is replaced by absorption system. The fuel used in the production of the future system decreases and also the emissions. Then, the future system becomes an opportunity from an environmental and economical point of view. At higher purchase electricity prices predicted in the open electricity market for an immediately future, the future system will become more economically advantageous.
8
Ozmen, Emin Mehmet. "Part Cooling Analysis By Conformal Cooling Channels In Injection Molding." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12609186/index.pdf.
Повний текст джерелаАнотація:
Straight cooling channels are the most common method of controlling part temperature in
injection molding process. However, straight cooling channels are not enough to manage
temperature uniformity of the parts. In this work, a numerical study is conducted to decrease
cycle time and cost of the injection molded parts by using conformal cooling channels. For this
purpose, the commercial injection molding simulation program Moldflow is used.
The governing physical equations for injection molding were derived and presented. The
assumptions of the model were checked for simple geometries by comparing analytical results
and numerical results of Moldflow. Then, the effect of conformal cooling channels is
investigated for injection molding of a half cylinder shell part. It was seen that conformal cooling
channels cools part faster and more uniform than straight cooling channels without corruption on
the surface appearance.
Finally, a real life case study was presented. For this purpose, a refrigerator shelf that is
manufactured by the Arçelik Company was studied. The process was simulated using actual process parameters and simulation results were compared with production results. Then, the process was simulated using conformal cooling channels and compared with production results. It is seen that the cycle time of the refrigerator shelf was decreased considerably while preserving surface quality appearance.
9
Omma, Henrik Nilsen. "Jet-powered cooling cores : reversing cooling flows through AGN activity." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.419330.
Повний текст джерела
10
Aghasi, Paul P. "Dependence of Film Cooling Effectiveness on 3D Printed Cooling Holes." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1458893416.
Повний текст джерела
11
Chan, Ying-kit. "Strange star cooling." Click to view the E-thesis via HKUTO, 2005. http://sunzi.lib.hku.hk/hkuto/record/B3138254X.
Повний текст джерела
12
Chan, Ying-kit, and 陳英傑. "Strange star cooling." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B3138254X.
Повний текст джерела
13
Collins, Matthew C. J. "Casing effusion cooling." Thesis, University of Oxford, 2014. https://ora.ox.ac.uk/objects/uuid:8a7204f5-9436-4c11-b6d6-25aef0bff8f7.
Повний текст джерелаАнотація:
The design, modelling and testing of a film cooling system intended for the casing of an unshrouded HP turbine rotor is described in this thesis. Due to the dense network of small film cooling holes employed in such a system, this is often referred to as a casing effusion cooling scheme. Though there are patent references to such systems, there is as yet very limited published material on the aero thermal performance of such film cooling schemes. The casing of an unshrouded HP rotor is an incredibly hostile environment, witnessing the periodic passing of the HP rotor tips within close proximity at a frequency of ∼10 kHz. These blade passing events subject the casing to extremely large amplitude fluctuations of pressure and heat load, which may at first seem to preclude the use of a film cooling scheme. This thesis details many theoretical, computational and experimental advancements related to the research topic. Highlights include: The introduction of a new fundamental mechanism to the field of film cooling, the propagation and reflection of pressure waves within film cooling holes and the impact on film cooling performance. The development of new miniature thin film heat flux gauges manufactured using a new process. Sensor resolution is improved by a factor of seven. The first published computational model reporting heat transfer data on a film cooled rotor casing. Improvements to heat transfer data processing techniques and theory. These are applied to experimental work to produce the highest resolution heat transfer data obtained on the casing of a scaled rotating transonic HP rotor for both uncooled and cooled geometries. Computational models are used to demonstrate that coolant injection on the rotor casing reduces the over-tip leakage mass flow, offsetting the spoiling and mixing losses that film cooling schemes introduce. Much of the work in this thesis is based on papers that have been submitted to or are pending submission. To date three papers have been presented at conference with two published in journals and the third recommended and pending journal publication. Two other papers are pending submission. A patent has also been filed with the European and American patent office regarding novel film cooling hole shapes designed to make use of acoustic effects.
14
Ryjkov, Vladimir Leonidovich. "Laser cooling and sympathetic cooling in a linear quadrupole rf trap." Texas A&M University, 2003. http://hdl.handle.net/1969.1/1637.
Повний текст джерелаАнотація:
An investigation of the sympathetic cooling
method for the studies of large ultra-cold molecular ions in a quadrupole ion trap has been conducted.Molecular dynamics simulations are performed to study the rf heating mechanisms in the ion trap. The dependence of
rf heating rates on the ion temperature, trapping parameters,
and the number of ions is obtained. New rf heating mechanism
affecting ultra-cold ion clouds exposed to laser radiation is described.The saturation spectroscopy setup of the hyperfine spectra
of the molecular iodine has been built to provide an accurate frequency reference for the laser wavelength. This reference is used to obtain the fluorescence lineshapes of
the laser cooled Mg$^+$ ions under different trapping conditions.The ion temperatures are deduced from the measurements, and
the influence of the rf heating rates on the fluorescence lineshapes
is also discussed. Cooling of the heavy ($m=720$a.u.) fullerene ions to under 10K by the means of the sympathetic cooling by the Mg$^+$ ions($m=24$a.u.) is demonstrated. The single-photon imaging system has been developed and used to obtain the images of the Mg$^+$ ion crystal structures at mK temperatures.
15
Birkne, Oskar, and Jana Hanke. "Cooling a Bottle of Champagne: Mathematical Models for the Cooling Process." Thesis, KTH, Teoretisk fysik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-103462.
Повний текст джерела
16
Yang, Yifan. "Personal-portable Cooling Garment Based on Adsorption Vacuum Membrane Evaporative Cooling." Thesis, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19835.
Повний текст джерелаАнотація:
A cutting edge man-portable AVMEC cooling garment was demonstrated to be able to provide sufficient cooling for personnel working at mediate activity loads. Studies were first carried out in a well controlled vacuum desiccator at room temperature to elucidate the effects of several key parameters on the performance of an AVEC device, which was similar to AVMEC except that membrane was not involved. Under the best condition, an average cooling capacity of 179 W/M2 was achieved in a period of four hours and cooling continued at a slowly declining rate for another four hours afterward. The temperature of water was maintained at approximately 12.5 oC after the pseudo steady state was established. Then, it was shown that the AVMEC cooling pads were able to provide a cooling capacity of 277.4 W/m2 in a 37 oC ambient environment (incubator). The temperature of the cooling core surface was maintained in a range of 20 – 21.8 oC in the one-hour test period. No power supply was required except for the initialization stage, which took 5 minutes. Furthermore, human subject tests with or without wearing NWBC (Nuclear Warfare Biological and Chemical) suit demonstrated that, a AVMEC garment composed of 12 cooling pads were able to maintain the core body temperature of the subjects below 38.5 oC for up to 90 minutes while the subject was walking on a treadmill at a speed of 2 miles per hour in an environment of 40 oC and 50% RH (relative humidity). These results indicate that the AVMEC garment is a promising man-portable personal cooling technology.
17
Chambers, Andrew. "An investigation of impingement cooling applied to turbine blade cooling passages." Thesis, University of Oxford, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400071.
Повний текст джерела
18
Yuen, Hong Chuen Raymond. "An investigation of thermal conditions in spark ignition engines." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366457.
Повний текст джерела
19
Johansson, Eric. "Optimization of Ground Source Cooling Combined with Free Cooling for Protected Sites." Thesis, KTH, Tillämpad termodynamik och kylteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98657.
Повний текст джерелаАнотація:
Ground source cooling is commonly used for cooling of electronics in protected sites. Sometimes the boreholes are combined with free cooling from the air using a dry cooler to reduce the amount and length of the boreholes, which is the biggest part of the costs. The dry cooler can have two different running modes. In unloading mode the dry cooler is started at a certain temperature and the fans are slowed down at low temperatures so that the cooling power never exceeds the cooling demand. The extracted cooling is used to unload the boreholes. In recharging mode the dry cooler is started at a certain temperature and is operating at full capacity below this temperature. The excess cooling that is extracted in this mode is used to recharge the boreholes. The numerical simulation tool COMSOL Multiphysics was used to evaluate the borehole performance. The software can simulate tilted boreholes with good accuracy and makes it possible to adjust the geometry in any desired way. In this thesis, the performance of a 100 kW ground source cooling system is evaluated for a number of cases both with and without dry coolers in different running modes and sizes. The best solution in respect to life cycle cost, technical feasibility and environmental impact is chosen to be an unloading case with a dry cooler with 100 kW capacity at 8 °C. Using only boreholes gives less carbon dioxide emissions but much higher costs.
20
Nowlin, Scott Raymond. "The use of intersecting film cooling passages for nozzle guide vane cooling." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670018.
Повний текст джерела
21
Martin, Christopher L. "Study of cooling production with a combined power and cooling thermodynamic cycle." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0008332.
Повний текст джерела
22
Leblanc, Christopher N. "Design, Analysis, and Development of a Tripod Film Cooling Hole Design for Reduced Coolant Usage." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/19206.
Повний текст джерелаАнотація:
This research has a small portion focused on interior serpentine channels, with the primary focus on improving the effectiveness of the film cooling technique through the use of a new approach to film cooling. This new approach uses a set of three holes sharing the same inlet and diverging from the central hole to form a three-legged, or tripod, design. The tripod design is examined in depth, in terms of geometric variations, through the use of flat plate and cascade rigs, with both transient and steady-state experiments. The flat plate tests provide a simplified setting in which to test the design in comparison to other geometries, and establish a baseline performance in a simple flow field that does not have the complications of surface curvature or mainstream pressure gradients. Cascade tests allow for testing of the design in a more realistic setting with curved surfaces and mainstream pressure gradients, providing important information about the performance of the design on suction and pressure surfaces of airfoils. Additionally, the cascade tests allow for an investigation into the aerodynamic penalties associated with the injection hole designs at various flow rates. Through this procedure the current state of film cooling technology may be improved, with more effective surface coverage achieved with reduced coolant usage, and with reduced performance penalties for the engine as a whole. This research has developed a new film hole design that is manufacturable and durable, and provides a detailed analysis of its performance under a variety of flow conditions. This cooling hole design provides 40% higher cooling effectiveness while using 50% less coolant mass flow. The interior serpentine channel research provides comparisons between correlations and experiments for internal passages with realistic cross sections.Ph. D.
23
Hillenbrand, Gerd. "Laser cooling of atoms." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259952.
Повний текст джерела
24
Steane, A. M. "Laser cooling of atoms." Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315817.
Повний текст джерела
25
Kim, J.-K. "Cooling water system design." Thesis, University of Manchester, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504687.
Повний текст джерела
26
Syed, Athar. "Optimal solar cooling systems." Thesis, London South Bank University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.434431.
Повний текст джерела
27
Lindgren, Arne. "Development of Brake Cooling." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-31225.
Повний текст джерелаАнотація:
Sports cars need efficient brake cooling as they shall perform well during hard driving conditions, like for example race track driving. Most sports cars use ducts that capture ambient airflow and directs this flow over the brakes to improve the cooling. This project was conducted in cooperation with Koenigsegg Automotive AB and aims to develop more efficient brake cooling ducts for their cars. Computational Fluid Dynamics was used to analyse the convective cooling of the brake disc and the pads. First was the cooling with the previously used ducts analysed in order to establish a reference. Then new concepts were created, analysed and developed in an iterative process. A design is proposed, which have the inlet in the centre of the wheel axle and that directs the air through radial channels to the brake disc. The simulations indicate that the proposed design results in 14% higher heat transfer rate compared to the previously used cooling solution. In addition to the cooling ducts, some passive cooling devices were also simulated. Simulations with these in combination with the proposed design, indicate up to 25% increase in heat transfer rate, but this cannot be fully confirmed due to limitations in the simulation model.Sportbilar behöver effektiv bromskylning eftersom de ska prestera väl under hårda körförhållanden, som till exempel bankörning. De flesta sportbilar använder kanaler som fångar omgivande luftflöde och riktar detta flöde över bromsarna för att förbättra kylningen. Detta projekt genomfördes i samarbete med Koenigsegg Automotive AB och syftar till att utveckla effektivare bromskylkanaler till deras bilar. Computational Fluid Dynamics användes för att analysera den konvektiva kylningen av bromsskivan och bromsbeläggen. Först analyserades kylningen med den tidigare använda bromskylkanalen i syfte att skapa en referens. Sedan skapades nya koncept som analyserades och utvecklades i en iterativ process. En konstruktion föreslås, som har inloppet i centrum av hjulaxeln och som sedan styr luften genom radiella kanaler till bromsskivan. Simuleringarna indikerar att den föreslagna konstruktionen resulterar i 14% högre värmeöverföringshastighet än den tidigare använda bromskylningslösningen. Förutom kylkanalerna har några passiva kylanordningar också simulerats. Simuleringar med dessa i kombination med den föreslagna konstruktionen, indikerar upp till 25% ökning av värmeöverföringshastigheten, men detta kan inte helt bekräftas på grund av begränsningar i den använda simuleringsmodellen.
28
Nord, Axel, and Zhao Yiqing. "Immersed Cooling of Electronics." Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194367.
Повний текст джерелаАнотація:
This master thesis is supported by Ericsson to conduct research on immersed liquid cooling of electronics. By this technology, the liquid will be in direct contact with the electronics. The research begins with investigations in industrial background, literature review and theory in heat transfer. According to the knowledge from those investigations, different liquid cooling systems including indirect, direct and immersed liquid cooling systems are introduced. The experiment consists of three parts: air cooling, single-phase and two-phase liquid cooling. Those three parts are with the same test board with adjustable heat resources in the same geometry. In the first part, an air flow channel is used for testing air cooling, by which immersed liquid cooling can be compared to traditional technology. In the second part, an immersed liquid cooling system is designed and constructed with detailed explanation. Liquid NovecTM 7200 is used as working liquid. In the third part, a huge number of data has been collected during the whole process of boiling, through which a boiling curve for NovecTM 7200 has been acquired. Then comparisons between those three technologies have been made. The feasibility of immersed liquid cooling on an industrial scale has also been discussed. Based on the experiments and analyses, a careful conclusion that electronics with liquid cooling has a larger heat flux limit than with today’s air cooling but with some practical problems can be drawn.
29
Hossain, Mohammad Arif. "Sweeping Jet Film Cooling." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1586462423029754.
Повний текст джерела
30
Rayner, Anton. "Laser cooling of solids /." St. Lucia, Qld, 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16448.pdf.
Повний текст джерела
31
Björk, Lars. "Construction of cooling rig and investigation of cooling sensitivity for aluminum crash alloy." Thesis, KTH, Materialvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-160902.
Повний текст джерелаАнотація:
The work presented in this master thesis deal with the issue of quenching, investigation regarding different cooling rates and its effect on the material properties of aluminum alloy in the 6xxx series used for crash purposes in cars, such as crash boxes, beams and other crash relevant parts. Precipitation of Mg2Si due to different cooling rates affects the material properties such as crash performance, thus the aluminum alloy used is sensitive to different cooling rates. In order to perform tests with different cooling rates a cooling rig was constructed. In order to evaluate the different cooling rates both mechanical testing such as tensile test and 3-point bending test and compression test were performed. Also analyses with scanning electron microscope/energy-dispersive x-ray spectroscopy were performed to estimate grain boundary decoration of Mg2Si due to the different cooling rates. Furthermore LOM analyses were performed to evaluate if the experimental setup had any effect on material properties such as grain size. The constructed cooling rig produced different cooling rates with reliable repeatability as intended. Cooling rates between 130 ̊C/s and 20 ̊C/s were accomplished. Mg2Si occurred in all investigated test samples with various amounts. Higher cooling rates decreases the precipitation of Mg2Si to the grain boundaries, higher cooling rates also increased the bending angle achieved from the 3-point bending test. Furthermore, extensive solution heat treatment at elevated temperatures leads to grain growth.
32
Gayeski, Nicholas (Nicholas Thomas). "Predictive pre-cooling control for low lift radiant cooling using building thermal mass." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/61508.
Повний текст джерелаАнотація:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Architecture, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 143-159).
Low lift cooling systems (LLCS) hold the potential for significant energy savings relative to conventional cooling systems. An LLCS is a cooling system which leverages existing HVAC technologies to provide low energy cooling by operating a chiller at low pressure ratios more of the time. An LLCS combines variable capacity chillers, hydronic distribution, radiant cooling, thermal energy storage and predictive control to achieve lower condensing temperatures, higher evaporating temperatures, and reductions in instantaneous cooling loads by spreading the daily cooling load over time. The LLCS studied in this research is composed of a variable speed chiller and a concrete-core radiant floor, which acts as thermal energy storage. The operation of the chiller is optimized to minimize daily energy consumption while meeting thermal comfort requirements. This is achieved through predictive pre-cooling of the thermally massive concrete floor. The predictive pre-cooling control optimization uses measured data from a test chamber, forecasts of controlled climate conditions and internal loads, empirical models of chiller performance, and data-driven models of the temperature response of the zone being controlled. These data and models are used to determine a near-optimal operational strategy for the chiller over a 24-hour horizon. At each hour, this optimization is updated with measured data from the previous hour and new forecasts for the next 24 hours. The novel contributions of this research include the following: experimental validation of the sensible cooling energy savings of the LLCS relative to a high efficiency split system air conditioner - savings measured in a full size test chamber were 25 percent for a typical summer week in Atlanta subject to standard efficiency internal loads; development of a methodology for incorporating real building thermal mass, chiller performance models, and room temperature response models into a predictive pre-cooling control optimization for LLCS; and detailed experimental data on the performance of a rolling-piston compressor chiller to support this and future research.
by Nicholas Thomas Gayeski.
Ph.D.
33
Alharbi, Abdulrahman. "Investigation of sub-wet bulb temperature evaporative cooling system for cooling in buildings." Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/27806/.
Повний текст джерелаАнотація:
The work presented in this thesis investigates design, computer modelling and testing a sub-wet bulb temperature evaporative cooling system for space air conditioning in buildings. The context of this evaporative cooling technology design is specifically targeted at locations with a hot and dry climate such as that prevailing in most regions of Middle East countries. The focus of this technology is to address the ever-escalating energy consumption in buildings for space cooling using mechanical vapour compression air conditioning systems. In this work, two evaporative cooling configurations both based on sub-wet bulb temperature principle have been studied. Furthermore, in these designs, it was sought to adopt porous ceramic materials as wet media for the evaporative cooler and as building element and use of heat pipes as heat transfer devices. In the first test rig, the prototype system uses porous ceramic materials as part of a functioning building wall element. Experimental and modelling results were obtained for ambient inlet air dry bulb temperature of 30 and 35oC, relative humidity ranging from 35% to 55% and intake air velocity less than 2 (m/s). It was found that the design achieved sub-wet bulb air temperature conditions and a maximum cooling capacity approaching 242 W/m2 of exposed ceramic material wet surface area. The wet bulb effectiveness of the system was higher than unity. The second design exploits the high thermal conductivity of heat pipes to be integrated as an effective heat transfer device with wet porous ceramic flat panels for evaporative cooling. The thermal performance of the prototype was presented and the computer model was validated using laboratory tests at temperatures of 30 and 35oC and relative humidity ranging from 35% to 55%. It was found that at airflow rates of 0.0031kg/s, inlet dry-bulb temperature of 35oC and relative humidity of 35%, the supply air could be cooled to below the inlet air wet bulb temperature and achieve a maximum cooling capacity of about 206 W/m2 of wet ceramic surface area. It was shown that the computer model and experimental tests are largely in good agreement. Finally, a brief case study on direct evaporative cooling thermal performance and environmental impact was conducted as part of a field trip study conducted on an existing large scale installation in Mina Valley, Saudi Arabia. It was found that the evaporative cooling systems used for space cooling in pilgrims’ accommodations and in train stations could reduce energy consumption by as much as 75% and cut carbon dioxide emission by 78% compared to traditional vapour compression systems. This demonstrates strongly that in a region with a hot and dry climate such as Mina Valley, evaporative cooling systems can be an environmentally friendly and energy-efficient cooling system compared to conventional vapour compression systems.
34
SARASKETA, ZABALA ELIXABET. "Technological and economic evaluation of district cooling with absorption cooling systems in Gävle (Sweden)." Thesis, University of Gävle, Ämnesavdelningen för energi- och maskinteknik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-4762.
Повний текст джерела
35
Modlin, James Michael. "Hypersonic aerospace vehicle leading edge cooling using heat pipe, transpiration and film cooling techniques." Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/16347.
Повний текст джерела
36
Luu, Trang(Trang N. ). "Impact of surface area and porosity on the cooling performance of evaporative cooling devices." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/129010.
Повний текст джерелаАнотація:
Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, September, 2020Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 110-111).
Evaporative cooling devices are low-cost, low-energy solutions for post-harvest storage of fruits and vegetables on farmlands. Surface area and porosity are two design parameters that affect the cooling devices' evaporation rate and cooling performance. Both design parameters lack prior systematic testing that methodically varies levels of surface area and material porosity to understand their effects on these devices' cooling performance (e.g. maximum temperature drop, duration of high internal relative humidity, cooling efficiency and total cooling). For fruits and vegetables, storage environments with low temperature and high humidity are critical to reduce deterioration. In this thesis, ridges were cut into the outer wall of pot-in-pot evaporative cooling devices at four different interridge distances to vary total available surface area. Sawdust was added to clay in different ratios to create devices with varying porosity.
A new performance metric of total cooling is also introduced to account for the maximum temperature drop and the total duration of evaporative cooling. The surface area experiments reveal that adding corrugations on the surface introduces competing effects between increased surface area for water evaporation and decreased vapor concentration gradient inside of the corrugations' troughs; consequently, among the devices with corrugations, the amount of total surface area does not always correlate with cooling performance. Between the devices with some surface corrugation and the device without corrugation, the devices with corrugation do consistently achieve greater temperature drops. However, the devices with corrugation are unable to maintain temperature drops and high levels of internal relative humidity for as long as the device without corrugation. The porosity experiments conclude that the greater the porosity in the device's outer vessel, the greater the maximum temperature drop.
This is due to the reduced transport resistance during water and moisture movement to the device's surface. Higher percentages of porosity lead to faster evaporation rates which deplete the amount of water inside the devices quicker and explain why the temperature drops and internal relative humidity of the more porous devices do not last as long as the temperature drops and internal relative humidity of the less porous devices. This thesis investigates two design parameters of cooling devices and shows that increasing surface area and porosity increases maximum temperature drops but decreases both the duration of temperature drops and high internal relative humidity. Between the two design parameters, increasing porosity is the more practical and less burdensome solution to improve the overall performance of evaporative cooling devices for low-resource communities.
by Trang Luu.
S.M.
S.M. Massachusetts Institute of Technology, Department of Mechanical Engineering
37
Pettersson, Marcus. "Cooling Potential of Methane in Rocket Nozzle Cooling Channels : A Conjugate Heat Transfer Analysis." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-264355.
Повний текст джерелаАнотація:
The use of hydrocarbons as fuel in rocket propulsion has been of great interest to the aerospace industry in recent years. Specifically, natural gas with a high content of methane has taken the interest of several actors, among them Sweden-based GKN Aerospace who in collaboration with KTH Royal Institute of Technology have started the MERiT project. In this project, the potential of methane as a fuel is explored through conjugate heat transfer analysis of a cooling channel geometry on a test rig. The goal is partly to find what the cooling potential of the methane is, and partly to determine the risks of thermal cracking occurring in the cooling channel. This report aims to provide a CFD analysis of the behavior of a test rig developed in earlier stages of the project. The analysis is to be used to provide design points that real experiments can be based upon. Studied behaviors include limitations regarding overheating, choke in the cooling channel and efficiency of the rig. In addition to this, the fluid temperature is studied in order to provide an estimate of which design points provide the highest potential risk of thermal cracking. In experiments, this potential risk is to be evaluated and explored in order to judge the viability of methane as a fuel. From this thesis a database of design points has been built regarding two potential channel geometries with different alloy materials. The post process and gathering of data are designed in such a way that specific behaviors can be monitored depending on a specific input. Inputs include mass flow, heat flux, inlet temperature and outlet pressure of the test rig. These were parametrized such that 243 specific design points could be examined for each channel geometry. Concluding this thesis, it was found that 131 of the cases examined for the first channel geometry were within the realm of being useful, and that a few cases fall within the realm of being at risk for coking. The risk for choke in the cooling channel is apparent at high mass flows and low pressures. The efficiency is heavily tied to heat flux and inlet temperature but shifts to be more dependent on Reynold’s number when cases with unintended behavior are filtered out.Användningen av kolväten som bränsle i syfte att driva rymdfarkoster har intresserat flyg- och rymdindustrin under de senaste åren. Naturgas med ett högt innehåll av metan har fångat intresset av flera aktörer, däribland Sverige-baserade GKN Aerospace som i ett samarbete med KTH Kungliga Tekniska Högskolan har startat projektet MERiT. Projektet avser att utforska metans potential som bränsle genom en kombinerad värmeöverföringsanalys för en kylkanal i en raketmotordysa. Målet är delvis att fastställa vilken kylningspotential metan har samt att undersöka när koksning uppstår i kylkanalen. Den här rapporten ämnar kartlägga arbetet med en CFD-modell med avsikten att fastställa beteendet för en testrigg som utvecklats i tidigare delar av projektet. Analysen skall användas som en databas för att generera designpunkter som kan användas i verkliga experiment. De beteenden som studeras inkluderar begränsningar på grund av överhettning, chokning på grund av överljudshastigheter och hur effektivt gasen absorberar värmen som flödar in i riggen. Utöver detta studeras gasens temperatur i ett försök att kartlägga fall som har högst risk för koksning. Denna risk skall utvärderas och utforskas genom verkliga experiment för att bedöma hur pålitligt metan är som bränsle. Från denna studie har databaser av designpunkter genererats för två kanalgeometrier innehållande två olika legeringsstål. Efterbehandlingen och insamlingen av data från databaserna är upplagda på ett sådant sätt att specifika beteenden kan studeras beroende på en specifik input. Dessa inputs inkluderar massflöde, värmeväxling, inloppstemperatur och utloppstryck för testriggen. För att utveckla processen sattes dessa upp i parametrar som genererade 243 unika designpunkter för varje kanalgeometri. Sammanfattningsvis var 131 av designpunkterna för den första kanalen användbara, samt att vissa av dessa hamnar inom vad som kan konstateras ett temperaturområde som riskerar koksning. Risken för chokning i kylkanalen är tydlig vid höga massflöden och låga utloppstryck. Den övergripande effekten av riggen fanns vara starkt knuten till värmeväxling och inloppstemperatur, men går över till att vara mer beroende av Reynoldstalet när oönskade fall sorteras bort.
38
Strater, Kurt F. "Countercurrent cooling of blown film." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66003.
Повний текст джерела
39
Häller, Thomas Vincent. "Improved altertness through forehead cooling /." [S.l.] : [s.n.], 2009. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
Повний текст джерела
40
Jiang, Yan. "Noise from Train Cooling Fans." Licentiate thesis, KTH, Aeronautical and Vehicle Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10082.
Повний текст джерелаАнотація:
This thesis concerns a study undertaken on a railway vehicle cooling fan system. Several design modifications were proposed and tested in the laboratory in order to evaluate different noise control measures. The most effective noise control measure involving combining lots of different measures gave 7 dB(A) noise reduction. Furthermore a modification by replacing the axial fan by a radial fan can even reduce the radiated sound power by 10 dB(A). The transfer functions were also examined for a dipole source to acoustic pressure in the far field to evaluate the acoustic loading created by the cooling fan enclosure. One fan was taken out from the complete unit and mounted between two acoustic test chambers to measure the effect of various parameters on the acoustic source strength (power) under controlled conditions. To predict accurate data of radiated sound power for comparison with the experimental work, two models have been developed: one model using the Farassat formula for a rotating dipole and the other model based on a 3D acoustic-vortex model. The heat exchangers in the cooling unit can have a significant effect on sound emitted from a cooling fan. An acoustic model based on so called equivalent fluid model for an anisotropic medium was derived to evaluate the sound transmission and the absorption through a parallel plate type of heat exchanger.
41
Hofmeijer, Erik, and Martin Nilsson. "Construction of a cooling step." Thesis, KTH, Maskinkonstruktion (Inst.), 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-100139.
Повний текст джерелаАнотація:
Ett livsmedelsföretag har manuell kylning av pasta mellan deras kokningsmaskin och deras kylningsmaskin. Kylningen är viktig för att avbryta kokningen av pastan. Detta examensarbete behandlar konstruktionen av ett koncept vars uppgift är att automatisera kylningen av pasta inom detta livsmedelsföretag. Konceptets uppgift är att sköta transporten mellan kokdelen och kyldelen samt att kyla pastan från 100 till 40 °C. Uppgiften har åtagits av TB svets och rörmontage. Via detta företag har ett examensarbete skapats för att komma fram till ett koncept som löser uppgiften. Denna rapport är skapad för att förklara hur det valda konceptet tagits från ett embryo i konceptgenereringen, till att under processens gång utvecklas till ett detaljerat koncept. Den tekniska grunden lades i den tekniska referensramen. I samband med konceptgenereringen skapades ett antal delkoncept. Dessa slogs samman till hela koncept. Genom dimensionerande och prestanda relaterade beräkningar undersöktes deras realiserbarhet. Under arbetets gång minskades antalet koncept till att slutligen bli ett. Detta vidareutvecklades genom att bestämma konstruktionslösning och tekniska komponenter. Det valda konceptet kan delas upp i två delar. En del som kopplas till kokmaskinen och som består av ställdon, en knuffande stång och en tippande kant. Dess funktion är att "knuffa" korgar med färdigkokt pasta över till nästa del. Denna del består av ett transportband som är monterat i ett kar. Till denna del hör även ett vattenspolningssystem och galler. Korgarna landar "upp och ned" vända på gallret vilket innebär att pastan faller ned på transportbandet. I och med detta startar vattenspolningssystemet vars uppgift är att kyla ned pastan. När pastan nått rätt temperatur transporteras pastan till kylmaskinen. Om konceptet vidareutvecklas och implementeras innebär det att ett arbetsmoment som är hårt och slitsamt kan försvinna. Detta leder både till ökad hälsa och ekonomiska vinster. Kylningen kommer att ske med en högre jämnhet vilket kommer att öka kvalitén.A food company has a manual cooling of cooked pasta between their cooking machine and their cooling machine. Cooling of the pasta is important to stop the cooking process. This final thesis deals with the design of a concept whose function is to automate the cooling of pasta in the food business. The concept is to handle the transportation between cooking part and refrigerator compartments and to cool the pasta from the 100 to 40 °C (212 °F to 104 °F). TB Rör och Svetsmontage has undertaken the task. Through this company this thesis was created to come up with a concept that solves the task. This report is intended to explain how the selected concept was taken from an embryo in the concept generation, which during the process became a developed detailed concept. The technical basis was given in the technical frame of reference. In connection with the concept generation a number of sub drafts were made. These were merged into the whole concepts. By design and performance-related calculations the realization of the concepts were examined. In the process, the numbers of concepts was reduced to eventually become one. That concept was further developed by determining the design solution and technical components. The chosen concept can be divided into two parts. One part is linked to the cooking machine and is consisting of actuators, a pushing rod and a tipping edge. Its function is to "push" baskets of cooked pasta to the next part of the concept. This part consists of a conveyor which is mounted in a vat. In This part also includes water flushing systems and grids. Baskets lands "upside down" on the grid so that the pasta can fall on the conveyor belt. This will start the water flushing system whose function is cooling the pasta. When the pasta has reached the right temperature the pasta will be transported to the cooling machine. If the concept will be further developed and implemented, it means that an operation which is hard and wear may disappear. This leads to increases in both health and economic benefits. Cooling will occur with a higher smoothness which will increase the quality.
42
Tybrandt, Ola. "Distribution of Cooling to Avionics." Thesis, Linköpings universitet, Reglerteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-79031.
Повний текст джерелаАнотація:
In modern aircraft, one of the most difficult issues has been how to provide avionics with adequate cooling. Future versions of the fighter aircraft JAS 39 Gripen is equipped with new applications that have increased heat loads. In previous versions of the JAS 39 Gripen avionics was cooled by zero degree air and fuel, but in the next version a liquid loop will be installed to cool the new radar.The fluid in the liquid loop is cooled to proper temperature by pressurized bleed air from the engine which is cooled by ram air. The air to cool the avionics is produced the same way and this is a very expensive process for the airplane which lowers its performance. It is important to minimize the production of cooling air and therefore three new adjustable valves that provide various components of cooling air are installed in the next version of the JAS 39 Gripen. The cooled and pressure controlled air from the engine is distributed between different avionic shelves, each containing a set of components. Depending on the type of tasks performed and current flight mode of the aircraft the requirement of functions which should be active varies and therefore also the cooling demand to avionics. The first part of this thesis studies the overall priority of how the engine bleed shall be used. This part of the thesis results in a decision basis for the distribution of cooling air to be regulated in the absence of full cooling capacity. The amount of cooling which must be distributed to the radar is proportional to its developed power which varies widely depending on the radar’s operational mode. Since the pump which determines the liquid flow velocity operates at a constant speed is the regulation of cooling to the radar is controlled by varying the bleed air flow into the heat exchanger which cools the fluid and thus the temperature of the fluid has when it reaches the radar. This part of the thesis creates a control algorithm for controlling the airflow into the heat exchanger. The regulation keeps the fluid inlet temperature to the radar within the range of +25 ± 5 ˚ C and the gradient of the temperature less than 0.5° C per second. The PI-controller with the feed-forward filter succeeded in controlling the temperature of the liquid as it reached the radar within +25 ± 1° C, the temperature gradient requirement, 0.5° C per second, was also passed in all flight cases which were used to evaluate the controller. The PI-controller with feed-forward has a low convergence time and no static error. It also performs well when the measurement signals contain a lot of noise because of the controllers integrated low pass filter. The three new adjustable valves saves 12 to 97 g/s of cooling air for the different valve positions studied in this thesis, this corresponds to 9 - 70% of the total amount of controllable air to the avionics. Since the production of cooling air is a costly process for the aircraft, the use of all 3 valves is recommended.
43
Gao, Xuan. "Drop impact in spray cooling." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/63356.
Повний текст джерелаАнотація:
Spray cooling has enormous potential in addressing high-heat-flux thermal challenges in many cutting-edge technologies. In spray cooling, a flow of coolant drops is emitted from a spray nozzle and impacts a hot surface, which is covered by a flowing film. Heat transfers by convection from the surface to the liquid coolant, and the cooling performance is determined by the fluid dynamics of spray drops impacting the liquid film. The cooling mechanisms involved in spray cooling are still not clear, due to the lack of understanding of the heat transfer and fluid dynamics involved in the drop impact in spray cooling.
The research work puts focus on the drop impact in spray cooling, which is carried out in four major steps. The first step is to study spray impact cooling experimentally with focus on the cooling effects of nozzle positioning parameters including spray height and inclination angle. The positioning parameters are shown to have effects on global and local cooling as the drop impact is affected when changing the spray positioning. The second step is to experimentally and theoretically investigate the fluid dynamics of a single liquid drop impacting a flowing film. The third step is to evaluate heat transfer enhancement during a single drop impact. The work carried out in the second and third steps forms a comprehensive study on the thermal-fluidics of single drop impact on a flowing film. The fourth step moves on to the heat transfer enhancement of drop train impacting flowing films. A drop train is formed when drops are generated in groups, and each group has a consistent number of drops. A drop generator is combined with a special setup to generate drop trains with varied impact frequencies including group frequency (the generation rate of groups) and single frequency (the generation rate of single drops in each group). The results relate the cooling enhancement of continuous drop impact to important impact parameters including drop number, velocity, and impact frequencies.Applied Science, Faculty of
Engineering, School of (Okanagan)
Graduate
44
Al-Hinai, Hilal Ali Zaher. "Natural Cooling Techniques For Buildings." Thesis, Cranfield University, 1992. http://hdl.handle.net/1826/3591.
Повний текст джерелаАнотація:
Modern development in many Third World countries in the
hot regions of the world,, have been accompanied by the
construction of highly energy-wasteful buildings. The
interiors of these buildings have to be mechanically airconditioned
in order to achieve thermal-comfort conditions.
The consequence of this, has been the rapid increase in
electricity-generating plant capacity to match demand (of
which, for example at present in Oman, more than 70%
nationally is used for air-conditioning modern, energyinefficient
buildings).
The aim of this work was to find the most suitable way
of stabilising or even reducing the electricity demand in a
country like Oman. The first step taken to achieve this aim,
was to study and draw out lessons from the vernacular
architecture of the different climatic regions in Oman. This
has been followed by a literature survey that looks at
passive and active natural cooling techniques for buildings
in hot climates. Mathematical models were then developed to
analyze and compare those passive techniques that are most
suitable for an environment like that of Oman. Different ways
of reducing the heat gain through the roof were investigated
and compared. These include the addition of insulation,
shading, air-cooling of the roof when the ambient air
temperature is lower than that of the roof, and roof ponds.
Roof ponds were found to be the most effective of those
techniques analyzed. An improved design of the roof pond (the
Water Diode roof pond) that eliminates the need for covering
the roof pond during the day and uncovering it at night, was
suggested and analyzed. The analysis showed promising
results. Mathematical models were also developed to analyze and
compare dif f erent ways of reducing the heat gain through the
walls. These included the use of closed cavities, naturally
ventilated cavities, the addition of insulation, and the
effect of using brick as compared to concrete block. The
analysis suggested that the combination of a Water Diode roof
pond and insulated brick wall construction will reduce the
heat gain through the envelope of a single room by more than
90%, when compared to a room with un-insulated roof and
single-leaf concrete block walls.
An empirical validation of the mathematical models was
conducted. The results showed a good agreement between the
actual and predicted values. An economical analysis of the
commonly used roof and wall constructions in Oman, was also
conducted. This compared the life-cycle cost of nine
different construction techniques, with eight different airconditioning
schedules. The result of this analysis showed a
clear advantage of using roof insulation, reflective double
glazing, and insulated walls with brick outer-leaf and
concrete block inner-leaf.
45
Woods, Thomas F. "Heat pipes for electronic cooling." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/17213.
Повний текст джерела
46
Sheffield, Randolph J. "High heat flux spray cooling." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/17881.
Повний текст джерела
47
Thomas, Peter Andrew. "Cooling flows and galaxy formation." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329135.
Повний текст джерела
48
Ireland, Peter. "Internal cooling of turbine blades." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.235870.
Повний текст джерела
49
Pilorz, Stuart. "Galactic winds and cooling flows." Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242035.
Повний текст джерела
50
Forrest, David Alexander James. "The Muon Ionisation Cooling Experiment." Thesis, University of Glasgow, 2011. http://theses.gla.ac.uk/2839/.
Повний текст джерелаАнотація:
Outstanding areas of ambiguity within our present understanding of the nature and behaviour of neutrinos warrant the construction of a dedicated future facility capable of investigating the likely parameter space for the theta 1,3 mixing angle, the Dirac CP violating phase and clarifying the neutrino mass hierarchy. A number of potential discovery venues have been proposed including the beta beam, superbeam and neutrino factory accelerator facilities. Of these, the neutrino factory significantly outperforms the others. A neutrino factory will deliver intense beams of 10^21 neutrinos per year, produced from muons decaying in storage rings. This specification, coupled with the constraints of the short muon lifetime warrant the inclusion of a novel cooling channel to reduce the phase space volume of the beam to fall within the acceptance of the acceleration system. Ionisation cooling is the only viable cooling technique with efficacy over the lifetime of the muon, however, it has yet to be demonstrated in practice. In a full cooling channel, a muon beam will traverse a periodic absorber and accelerator lattice consisting of low Z absorbers enclosed by focusing coils and accelerating radio-frequency cavities. Energy loss in the absorbers reduces both transverse and longitudinal momentum. The latter is restored by the accelerating cavities providing a net reduction in transverse momentum and consequently reducing the phase space volume of the muon beam. The Muon Ionisation Cooling Experiment (MICE), under construction at the ISIS synchrotron at Rutherford Appleton Laboratory seeks to provide both a first measurement and systematic study of ionisation cooling, demonstrated within the context of a single cell prototype of a cooling channel. The experiment will evolve incrementally toward its final configuration, with construction and scientific data taking schedules proceeding in parallel. The stated goal of MICE is to measure a fractional change in emittance of order 10% to an error of 1%. This thesis constitutes research into different aspects of MICE: design and implementation of the MICE configuration database, determination of the statistical errors and alignment tolerances associated with cooling measurements made using MICE, simulations and data analysis studying the performance of the luminosity monitor and a first analysis of MICE Step I data. A sophisticated information management solution based on a bi-temporal relational database and web service suite has been designed, implemented and tested. This system will enable the experiment to record geometry, calibration and cabling information in addition to beamline settings (including but not limited to magnet and target settings) and alarm handler limits. This information is essential both to provide an experimental context to the analysis user studying data at a later time and to experimenters seeking to reinstate previous settings. The database also allows corrections to be stored, for example to the geometry, whereby a later survey may clarify an incomplete description. The old and new geometries are both stored with reference to the same period of validity, indexed by the time they are added to the configuration database. This allows MICE users to recall both the best-known geometry of the experiment at a given time by default, as well as the history of what was known about the geometry as required. Such functionality is two dimensional in time, hence the choice of a bi-temporal database paradigm, enabling the collaboration to run new analyses with the most up to date knowledge of the experimental configuration and also repeat previous analyses which were based upon incomplete information. From Step III of MICE onwards, the phase space volume, or emittance, of the beam will be measured by two scintillating fibre trackers placed before and after the cooling cell. Since the two emittance measurements are made upon a similar sample of muons, the measurement errors are influenced by correlations. This thesis will show through an empirical approach that correlations act to reduce the statistical error by an order of magnitude. In order to meet its goals MICE must also quantify its systematic errors. A misalignment study is presented which investigates the sensitivity of the scintillating fibre trackers to translational and rotational misalignment. Tolerance limits of 1 mm and 0.3 mrad respectively allow MICE to meet the requirement that systematic errors due to misalignment of the trackers contribute no more than 10% of the total error. At present, MICE is in Step I of its development: building and commissioning a muon beamline which will be presented to a cooling channel in later stages of MICE. A luminosity monitor has been built and commissioned to provide a measurement of particle production from the target, normalise particle rate at all detectors and verify the physics models which will be used throughout the lifetime of MICE and onwards through to the development of a neutrino factory. Particle identification detectors have already been installed and allow the species of particles to be distinguished according to their time of flight. This has enabled a study of particle identification, particle momenta and simulated and experimental beam profiles at each time of flight detector. The widths of the beam profiles are sensitive to multiple scattering and magnetic effects, providing an opportunity to quantify the success of the simulations in modelling these behaviours. Such a comparison was also used to detect offsets in the beam centre position which can be caused by misalignments of the detectors or relative misalignments in magnet positions causing asymmetrical skew in the magnetic axis. These effects were quantified in this analysis. Particle identification combined with the earlier statistical analysis will be used to show that the number of muons required to meet the statistical requirements of MICE can be produced within a realistic time frame for each beam configuration considered.