Aplikasi Thermochromic Liquid Crystal Untuk Mengamati Perpindahan Kalor Pada Permukaan Logam

Abstract

The purpose of this research was to observe the heat transfer on circular metal surface in contact with the surface of Thermochromic Liquid Crystal (TLC) R30C5W sheet, through the image on the surface of TLC during the heating process of metal. If the metal surface is in contact with the surface of TLC, the heat will move from the metal surface to TLC surface, and it is indicated by a color change on the surface of TLC. The original image is obtained in RGB is converted to hue image. The results showed, the value of mean hue increases by increasing temperature of metal surface. In addition, the value of hue along the center line of the circle image on the surface of TLC, fairly evenly distributed in the middle (inner circle) but diminishing the edges (right and left edges), which shows even further away from the edge of the metal surface, the thermal energy decreases because heat transfer occurs at the edges of the metal surface into the surrounding air.Keywords: Thermochromic Liquid Crystal (TLC), hue, heat transfer. ABSTRAKTujuan penelitian ini adalah untuk mengamati peristiwa perpindahan kalor pada area permukaan logam yang berbentuk lingkaran, yang bersentuhan dengan permukaan lembaran Thermochromic Liquid Crystal (TLC) R30C5W, melalui citra permukaan TLC selama proses pemanasan logam. Apabila permukaan logam tersebut bersentuhan dengan permukaan TLC, maka kalor akan berpindah dari permukaan logam ke permukaan TLC, dan ditunjukkan dengan terjadinya perubahan warna pada permukaan TLC. Citra asli yang diperoleh dalam format RGB dikonversi menjadi citra hue. Hasil menunjukkan, seiring dengan meningkatnya temperatur permukaan logam, nilai mean hue semakin meningkat. Selain itu, nilai hue sepanjang garis tengah lingkaran pada permukaan TLC, cukup merata di bagian tengahnya (lingkaran dalam) namun semakin berkurang di tepinya (tepi kanan dan kiri), yang menunjukkan semakin jauh dari tepi permukaan logam maka energi kalornya semakin berkurang, karena terjadi perpindahan kalor pada tepi permukaan logam ke udara di sekitarnya.Kata kunci: Thermochromic Liquid Crystal (TLC), hue, perpindahan kalor.

Transition Temperature in Thermochromic Liquid Crystals using Second-Order Features Extraction

“…Cholesteric liquid crystals also have dichroic properties which can absorb several directions of refracted light, causing light to become linearly polarized. When light is refracted and linearly polarized and enters the helical structure of the cholesteric liquid crystals, the light will experience circular polarization [13][14] .…”