Investigation of velocity and temperature fields in cooled and/or heated enclosures

In this doctorate thesis, velocity and temperature fields inside a heated cubical enclosure wereinvestigated numerically and experimentally.In the numerical part, four different problems were solved numerically. These are sidewallheated closed enclosure, bottom wall heated closed enclosure, natural convection in the samedirection as forced convection and natural convection in opposite direction to forcedconvection. For each problem, numerical results are presented in terms of dimensionlessresultant velocity, horizontal and vertical velocity. Dimensional horizontal and verticalvelocities were presented for three different sections of the enclosure. Velocity andtemperature contour maps were formed and dimensional temperature variation charts werepresented for three different sections. In addition, a heat transfer correlation was given forsidewall heated closed enclosure problem. Commercial software Fluent 6.0 was used innumerical studies.The experimental part of the thesis has two parts. In the first part, experimental velocitymeasurements were made for the four problems described above. Experimental studies wereperformed at nearly the same boundary conditions as numerical solutions. PIV (Particle ImageVelocimetry) was used for velocity measurements. PIV system was preferred because it doesnot disturb streamlines and measures velocity vectors in a short time. Reliability of PIVmeasurements of small velocities were checked and verified. Dimensionless resultantvelocity, horizontal velocity and vertical velocity values obtained from measurements werepresented. Dimensional horizontal and vertical velocity distributions were given for threedifferent sections of the enclosure. In the second part, temperature measurements were madeby using a total of 100 J type thermocouples. Dimensionless temperature distributions withinheated enclosure were given for four different problems. The temperature maps obtained fromnumerical solutions were verified experimentally.In the last part of the thesis, numerical and experimental results were compared with eachother. Generally good agreement was observed between the numerical and experimentalvelocity and temperature distributions. In addition, numerically obtained heat transfercorrelation was compared with similar expressions reported in literature and good agreementwas observed.Keywords: Velocity distribution within heated cubical enclosure, temperature distributionwithin heated cubical enclosure, PIV velocity measurement system, natural convection withincubical enclosure.JURY:1. Prof. Dr. Oktay ÖZCAN (Supervisor) Date: 01.09.20062. Prof. Dr. İsmail TEKE Page:1683. Prof. Dr. Seyhan ONBAŞIOĞLU