Isıtma ve soğutma amaçlı ısı pompası sisteminin modellenmesi

TEZ2175Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 1996.Kaynakça (s. 157-160) var.xviii, 160 s. ; rnk. res. ; 30 cm.

Impingement of vortex breakdown upon an edge :_flow structure and origin of loading

TEZ3537Tez (Doktora) -- Çukurova Üniversitesi, Adana, 2000.Kaynakça (s. 200-207) var.x, 214 s. ; res. ; 30 cm.

Design and introducing of a heat pump system for heating and cooling purposes

Bu çalışmada, bir ortamın ısıtılması ve soğutulması ile birlikte yıl boyunca sıcak su ihtiyacının karşılanmasını amaçlayan bir ısı pompası sisteminin tasarımı yapılmıştır. Tasarımı yapılan sistemin soğutucu akışkan ve su devrelerinin çalışma prensipleri anlatılmış ve sistemde kullanılan elemanlar tanıtılmıştır. İmalatı Makina Mühendisliği Bölümü laboratuarlarında gerçekleştirilmiş olan sistemin etkinliğinin deneysel olarak araştırılması amaçlanmıştır.In this study, a heat pump system for cooling in summer, heating in winter and supplying hot water during the year have been designed. Operating princips of refrigerant and water circuits of designed system and the elements used in the system are explained. The system is developed in the laboratories of Mechanical Engineering Department and it is aimed to investigate the efficiency of the system

Effect of pitching delta wing on vortex structures with and without impingement plate

Flow past the leading edge of a delta wing oscillating about its mid-cord in a pitch plane with a reduced frequency of K=0.74 generates primary vortices having mostly elongated shapes. Their shapes and orientations vary with the pitching angle of the delta wing in upstroke and downstroke directions. Unsteady flows around the impingement plate placed downstream of the delta wing and in the flow field downstream of the onset of vortex breakdown are characterized by the existence of unsteady large-and small-scale vortices. These time-dependent vortex core formations and breakdowns apply aerodynamic loads to the impingement plate. For the pitching delta wing, the development of the vortex core and degree of hysteresis are found to be a strong function of reduced frequency.Flow past the leading edge of a delta wing oscillating about its mid-cord in a pitch plane with a reduced frequency of K=0.74 generates primary vortices having mostly elongated shapes. Their shapes and orientations vary with the pitching angle of the delta wing in upstroke and downstroke directions. Unsteady flows around the impingement plate placed downstream of the delta wing and in the flow field downstream of the onset of vortex breakdown are characterized by the existence of unsteady large-and small-scale vortices. These time-dependent vortex core formations and breakdowns apply aerodynamic loads to the impingement plate. For the pitching delta wing, the development of the vortex core and degree of hysteresis are found to be a strong function of reduced frequency

Calculation of total solar radiation transmitted through window as heat gain

Bu çalışmada, ısı kazancı olarak camdan geçen toplam güneş radyasyonunu zamana bağlı olarak hesaplayan eşitlikler verilmiştir. Eşitlikler işlem sırasına göre yazılmıştır. CAMRAD isminde Pascal programlama dilinde bir bilgisayar programı geliştirilerek, Türkiyede'ki bazı şehirler için camdan ısı kazancı olarak geçen toplam güneş radyasyonunu gösteren çizelgeler hazırlanmıştır.In this study, equations of total solar radiation transmitted through window as heat gain have been given. The equations are written in sequence. By means of writing a computer program called CAMRAD, the tables of total solar transmitted through window as heat gain have been prepared for some provinces of Turkey

Investigation of interactions between a sphere wake and free surface

Bu çalışma, küre çapına göre tarif edilen Reynolds sayısının 2,5x103 ve 1x104 aralığında farklı daldırma yükseklikleri için açık bir su kanalında serbest su yüzeyi ve kürenin art izi bölgesi arasındaki akış yapısı etkileşimini sunmaktadır. Anlık ve zaman ortalaması alınmış hız alanı, akım çizgisi topolojisi, girdaplar ve hız konturları gibi akış modellerini göstermek için Parçacık Görüntülemeli Hız ölçme (PIV) ve boya görselleştirme teknikleri uygulanmıştır. Küre, serbest yüzeye kısmen daldırılma konumundan serbest yüzeyden iki küre çapı kadar aşağı doğru çeşitli daldırma konumlarına 0,25? h/D ?3,0 aralığında sabitlenmiştir. Daldırma oranı, küre alt kolunun serbest yüzey ile olan mesafesinin küre çapına oranı olarak tanımlanmıştır. Kürenin yerleştirildiği konumlara bağlı olarak, art izi bölgesinin özellikleri üç farklı akış olayı sergilemiştir. Bunlar; daldırma oranı 0,25? h/D ?1,0 aralığı için üniform akış bölgesi ve serbest yüzey arasındaki kısıtlı bir art izi bölgesi, daldırma oranı 1,25? h/D ?2,0 aralığı için serbest yüzey etkisinden dolayı simetrik olmayan akış modelleri ve daldırma oranı 2,5? h/D ?3,0 aralığı için simetrik akış yapıları olarak sınıflandırılmıştır. Akış fiziği açısından bahsedilen akış yapıları için daha detaylı sonuçlar karşılaştırılmalı olarak sunulmuş ve yorumlanmıştır.This paper presents flow-structure interaction between a sphere wake and a free water surface for different submerged elevations in an open water channel for Reynolds numbers in the range of 2.5x103 ?Re?1x104 based on the diameter of the sphere. Particle Image Velocimetry (PIV) and dye visualization techniques were performed to demonstrate flow patterns such as instantaneous and time-averaged velocity field, streamline topology, vortices, velocity contours. The sphere was fixed at various submerged locations from the piercing the free surface case to the two sphere diameters beneath the free surface in the range of 0.25? h/D ?3.0. Here, submerged ratio was defined as ratio of bottom shoulder of the sphere from the free surface to the sphere diameter. Depending on the sphere locations, characteristics of wake region exhibit three different flow phenomena. These are classified as; a restricted wake region between the free-surface and uniform flow stream for the submerged ratios of 0.25? h/D ?1.0, unsymmetrical flow patterns due to the free surface effect for the submerged ratios of 1.25? h/D ?2.0 and symmetrical flow structures for the submerged ratios of 2.5? h/D ?3.0. More detailed results for the aforementioned flow structures from the point of flow physics were comparatively presented and interpreted

Wake structures of two side by side spheres in a tripped boundary layer flow

Two independent spheres were placed in a side by side arrangement and flow structure in the wake region of the spheres was investigated with a Particle Image Velocimetry (PIV) system when the spheres were in a boundary layer over a flat plate as a special case. Reynolds number was 5000 based on the sphere diameter which was 42.5 mm. Boundary layer was tripped 8mm away from the leading edge of the flat plate with a 5 mm trip wire. The thickness of the hydrodynamically developed boundary layer was determined as 63mm which was larger than the sphere diameter of D=42.5mm. Wake region of the spheres was examined from point of flow physics for the different sphere locations in the ranges of 0≤G/D ≤1.5 and 0≤S/D ≤1.5 where G and S were the distance between the spheres and the distance between the bottom point of the spheres and the flat plate surface, respectively. Depending on the different sphere locations, instantaneous and time averaged vorticity data, scalar values of time-averaged velocity components and their root mean square (rms) values and time averaged vorticity data are presented in the study for the evaluation of wake region of the spheres. It is demonstrated that the gap between the two spheres and the interaction between the gap and the boundary layer greatly affects flow pattern, especially when spheres are located near to the flat plate surface, i.e. S/D=0.1 for 0≤G/D ≤1.5. Different distances between the spheres resulted in various flow patterns as the spheres were approached to the flat plate. The distance S/D=0.1 for all gap values has the strongest effect on the wake structures. Beyond G/D=1.0, the sphere wakes tend to be similar to single sphere case. The instantaneous vorticity fields of the side by side arrangements comprised wavy structures in higher level comparing to an individual sphere case. The gap flow intensifies the occurrence of small scale eddies in the wake region. The submersion rate of the spheres actually determines the characteristics of the wake region and is affected from boundary layer flow in a gradually decreasing manner

Control of the flow past a sphere near a flat wall using passive jet

Okbaz, Abdülkerim (Dogus Author)In the present investigation, interactions between the vortices shedding from a single sphere and the boundary layer flow over a flat plate with various gap ratios have been investigated at Re = 5000 using the techniques of dye visualization and Particle Image Velocimetry. A passive jet has been created to control the flow past the sphere by a hole drilled into the sphere from the forward stagnation point to the rear of the sphere with various diameters. The results show that the complex flow downstream of the sphere, which is occurred from the combination of 'Carman vortex street and the boundary layer over the flat plate can be controlled by a passive jet. Because the jet flow interrupts periodicity of the vortices shedding from the sphere by supplying fluid flow into the wake with relatively high velocity. Presence of the hole significantly attenuates the magnitudes of the turbulence characteristics. Furthermore, the magnitudes of the turbulence characteristics decrease with increasing the hole diameter depending on the location of the sphere in the boundary layer. However, a larger hole diameter can result in higher turbulence levels in the region of the passive jet. Hence, the effectiveness of the each case (the diameter of the hole) changes with the location of the sphere over the flat plate

Wake structures of two side by side spheres in a tripped boundary layer flow

Two independent spheres were placed in a side by side arrangement and flow structure in the wake region of the spheres was investigated with a Particle Image Velocimetry (PIV) system when the spheres were in a boundary layer over a flat plate as a special case. Reynolds number was 5000 based on the sphere diameter which was 42.5 mm. Boundary layer was tripped 8mm away from the leading edge of the flat plate with a 5 mm trip wire. The thickness of the hydrodynamically developed boundary layer was determined as 63mm which was larger than the sphere diameter of D=42.5mm. Wake region of the spheres was examined from point of flow physics for the different sphere locations in the ranges of 0≤G/D ≤1.5 and 0≤S/D ≤1.5 where G and S were the distance between the spheres and the distance between the bottom point of the spheres and the flat plate surface, respectively. Depending on the different sphere locations, instantaneous and time averaged vorticity data, scalar values of time-averaged velocity components and their root mean square (rms) values and time averaged vorticity data are presented in the study for the evaluation of wake region of the spheres. It is demonstrated that the gap between the two spheres and the interaction between the gap and the boundary layer greatly affects flow pattern, especially when spheres are located near to the flat plate surface, i.e. S/D=0.1 for 0≤G/D ≤1.5. Different distances between the spheres resulted in various flow patterns as the spheres were approached to the flat plate. The distance S/D=0.1 for all gap values has the strongest effect on the wake structures. Beyond G/D=1.0, the sphere wakes tend to be similar to single sphere case. The instantaneous vorticity fields of the side by side arrangements comprised wavy structures in higher level comparing to an individual sphere case. The gap flow intensifies the occurrence of small scale eddies in the wake region. The submersion rate of the spheres actually determines the characteristics of the wake region and is affected from boundary layer flow in a gradually decreasing manner