Otomobil dış aydınlatma gruplarında inovatif soğutma uygulamaları
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Dosyalar
Tarih
2020-06-26
Kurum Yazarları
Aktaş, Mehmet
Süreli Yayın başlığı
Süreli Yayın ISSN
Cilt Başlığı
Yayınevi
Bursa Uludağ Üniversitesi
Özet
Günümüzde kaliteli ışık çıktısı, estetik tasarıma elverişliliği, düşük güç tüketimi gibi bir çok avantaja sahip LED (Light Emitted Diode)’li otomotiv aydınlatma ürünleri yeni otomobillerde yaygın olarak kullanılmaya başlamıştır. Üzerinden geçen elektrik enerjisini 70-80% oranında ısı olarak açığa çıkaran LED yongalarında etkili ısıl yönetim yapılmadığı takdirde kalitesiz ve yoğunluğu az ışık çıktısı, kısa ömür gibi problemler meydana getirmektedir. Artan LED güçlerinde ısınma problemlerinin çözümünde geleneksel soğutma yöntemleri yetersiz kalmaktadır. Fakat otomotiv aydınlatma sistemlerinin araca uygulanmasında sınırlı ürün gövde hacminin olması, soğutma ünitelerine yeterli hacminin verilememesi, ürün üzerinde ağırlık artışları, homojen soğutmanın olmayışı gibi sorunları beraberinde getirmektedir. Sıvı soğutmalı sistemlerin yüksek soğutma kapasitesi, ortam koşullarından fazla etkilenmemesi ve kararlı yapısı, LED’li sistemlerin homojen soğutulmasına imkân sağlamaktadır. Bu avantajlarından dolayı bu tez çalışması kapsamında LED’li otomotiv aydınlatma elemanlarının soğutulmasında sıvı soğutmalı blok uygulamalarının hidrolik ve ısıl performansları incelenmiştir. Yapılan araştırma çalışmaları kapsamında ön aydınlatma ürünlerinde kullanılabilecek özgün LED baskı devre kartları tasarlanmış ve prototipi imal edilmiştir. Tasarlanan ve üretilen devre kartlarının sıvı soğutmalı blok tasarımları ile soğutulması hedeflenmiştir. Sıvı soğutmalı bloklarda ısıl performansının yüksek olması ve homojen soğutma yapması istenirken en az pompa gücü ve blok içi basınç düşümü sağlanması için tasarımda optimizasyon çalışması gerekmektedir. Bu nedenle farklı blok yapısı, LED gücü ve akışkan debi değerlerinde çalışılarak soğutma performansının iyileştirilmesi ve blok içi akışta basınç düşümünün en aza indirilmesine yönelik iyileştirme amacıyla hesaplamalı akışkanlar dinamiği (HAD) analizleri gerçekleştirilmiştir. En az blok içi akış basınç düşüşüne sahip, homojen soğutma ve en iyi ısı trasferini sağlayan iki blok yapısının prototipi imal edilerek LED baskı devre kartının soğutulması deneysel olarak incelenmiştir.Tasarımı ve üretimi yapılan LED baskı devre kartı ve optimize edilmiş blok yapısı seri üretimde olan ön aydınlatma komplesi içerisine yerleştirilerek HAD analizleri yapılmış ve deneysel olarak incelenmiştir. Geleneksel soğutmaya sahip seri üretimdeki otomotiv ön aydınlatma ürünü ile sıvı soğutmalı ön aydınlatma elemanının soğutma performansları ve ışık yoğunlukları karşılaştırılmıştır.
Today, automotive lighting products which has light emitting diodes with many advantages such as light output quality, aesthetic design, low power consumption have begun to be widely used in new cars. Unless effective thermal management is performed in LED (Light Emitted Diode) chips, which reveal the electrical energy passing through it as 70-80 % of heat, it creates problems such as poor quality and low light output and short life. Traditional cooling methods are insufficient in solving heating problems with increasing LED powers. Additionally, in the application of automotive lighting systems to the vehicle, there are problems such as limited body volume, insufficient volume for cooling units, weight limitations for product and lack of homogeneous cooling. Liquid cooled systems with high cooling capacity, not being affected by environmental conditions and stable structure allows homogeneous cooling for LED systems. Because of these advantages, hydraulic and thermal performances of liquid cooled block applications were investigated in the cooling of LED automotive lighting components within the scope of this thesis. Within the scope of the research studies, original LED printed circuit boards that can be used in front lighting products have been designed and prototypes have been manufactured. It is aimed to cool the designed and manufactured circuit boards with liquid cooled block designs. While it is desired to have a high thermal performance and homogeneous cooling in liquid cooled blocks, optimization work is required in the design to provide minimum pump power and pressure drop within the block. For this reason, computational fluid dynamics (CFD) analyzes were performed to improve cooling performance and to minimize pressure drop in block flow by working with different block structure, LED power and fluid flow values. The prototype of two block structures with minimum in block flow pressure drop, providing homogeneous cooling and the best heat transfer was manufactured and cooling of the LED printed circuit board was experimentally examined. Designed and produced LED printed circuit board and optimized block structure were placed in the front lighting assembly which is already in mass production and CFD analyzes were conducted and examined experimentally. The cooling performances and light output of the liquid cooled automotive lighting component and the automotive lighting product in mass production with traditional cooling were compared.
Today, automotive lighting products which has light emitting diodes with many advantages such as light output quality, aesthetic design, low power consumption have begun to be widely used in new cars. Unless effective thermal management is performed in LED (Light Emitted Diode) chips, which reveal the electrical energy passing through it as 70-80 % of heat, it creates problems such as poor quality and low light output and short life. Traditional cooling methods are insufficient in solving heating problems with increasing LED powers. Additionally, in the application of automotive lighting systems to the vehicle, there are problems such as limited body volume, insufficient volume for cooling units, weight limitations for product and lack of homogeneous cooling. Liquid cooled systems with high cooling capacity, not being affected by environmental conditions and stable structure allows homogeneous cooling for LED systems. Because of these advantages, hydraulic and thermal performances of liquid cooled block applications were investigated in the cooling of LED automotive lighting components within the scope of this thesis. Within the scope of the research studies, original LED printed circuit boards that can be used in front lighting products have been designed and prototypes have been manufactured. It is aimed to cool the designed and manufactured circuit boards with liquid cooled block designs. While it is desired to have a high thermal performance and homogeneous cooling in liquid cooled blocks, optimization work is required in the design to provide minimum pump power and pressure drop within the block. For this reason, computational fluid dynamics (CFD) analyzes were performed to improve cooling performance and to minimize pressure drop in block flow by working with different block structure, LED power and fluid flow values. The prototype of two block structures with minimum in block flow pressure drop, providing homogeneous cooling and the best heat transfer was manufactured and cooling of the LED printed circuit board was experimentally examined. Designed and produced LED printed circuit board and optimized block structure were placed in the front lighting assembly which is already in mass production and CFD analyzes were conducted and examined experimentally. The cooling performances and light output of the liquid cooled automotive lighting component and the automotive lighting product in mass production with traditional cooling were compared.
Açıklama
Anahtar kelimeler
Bağlantı noktası (jonksiyon) sıcaklığı, Printed circuit board, Otomotiv aydınlatma, Automotive lighting, HAD, CFD, Baskı devre kartı, LED, Sıvı soğutma, Laminer akış, Liquid cooling, Junction temperature, Laminar flow
Alıntı
Aktaş, M. (2020). Otomobil dış aydınlatma gruplarında inovatif soğutma uygulamaları. Yayınlanmamış doktora tezi. Bursa Uludağ Üniversitesi Fen Bilimleri Enstitüsü.