Yapay bir göldeki termal değişikliklerin bir boyutlu sayısal model ile simülasyonu

Öz

Bu çalışma yüksek sıcaklıktaki suyun göl ve rezervuar gibi akıntısız su kütlelerine verilmesini incelemektedir. Sayısal çalışmada PROBE isimli bir boyutlu (1B) sonlu hacim yazılımı kullanılmıştır. Yazılım, yüksek sıcaklıktaki suyun ve rüzgârın göl içindeki karışma süreçlerine etkisine, Koriolis etkisine ve güneş ışınımı etkisine açıklamalar getirmektedir. Bu koşullar termik santrallerdeki (kömür, doğalgaz, nükleer vb.) soğutma işlemleriyle alakalıdır. Mevsimsel doğal tabakalaşma ve termoklin oluşumu sayısal yöntemlerle ışık geçirim katsayısı, güneş ışınımı ve rüzgâr hızı kalibre edilerek gerçek bir göl için elde edilmiştir. Yapay bir göle su girişinde ve gölden su çıkışında oluşan termal tabakalaşma birçok durum için çalışılmıştır. Çalışma, yapay gölde, su giriş ve çıkışının kısa dalga ışınımı ve rüzgâr etkisi ile beraber düşey termal profile yaptığı etkiyi bir günlük (24 sa.’lik) süre için incelemektedir. 24 sa.’lik sonuçlar ortalama bir işlemci ve bilgisayar kullanılarak dakikalar içinde elde edilmiştir. Bu daha uzun vadedeki sonuçların kısa sürede elde edilebileceğini göstermiş ve bu tür kodların termal mühendislik uygulamalarında ne kadar kullanışlı olduğunu ortaya koymuştur.

Anahtar Kelimeler

• PROBE,Termoklin,Termik santral soğutma sistemleri,Işık geçirim katsayısı,Güneş ışınımı

Thermal changes in an artificial lake simulated using a one-dimensional numerical model

Abstract

This study focuses on release of high temperature water to still water bodies such as lakes and reservoirs. The numerical study is conducted using one dimensional (1D) finite volume code, PROBE. The code accounts for effect of high temperature water release, effect of wind over the lake in mixture processes, Coriolis’ effect and solar radiation. These conditions are relevant in cooling operations of thermal (coal, natural gas, nuclear etc.) power plants. Natural stratification and thermocline formation in a real lake is achieved by calibration of light extinction coefficient, solar radiation and wind velocity. The inflow and outflow of water to and from an artificial lake is studied under several scenarios when a thermal stratification exists. Study investigates the effect of inflow and outflow of water to an artificial lake under the effect of short wave radiation and wind for a period of one day (24 hours). Results for 24-hour simulations were obtained within minutes using an average processor and computer. This  shows how such 1D models are  viable tools in thermal engineering applications when long term results are required to be assessed in short time.

Keywords

• PROBE,Thermocline,Thermal power Plant cooling systems,Light extinction coefficient,Solar radiation

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