Understanding thermo-fluidic characteristics of a glass tube closed loop pulsating heat pipe: flow patterns and fluid oscillations

Temperature Evolution of Large-Scale Oscillating Heat Pipe with Methanol as the Working Fluid

“…One of the methods to evaluate OHP characteristics and performance is by observing the oscillation temperature of the evaporator, adiabatic and condenser. The observations of temperature evolution were analyzed and associated with visualization studies by previous researchers [2,9,12,15,20]. When heat was applied on the evaporator section, the evaporator temperature (T4) and adiabatic (T2 and T8) immediately increased with different degrees of slope (shown in Fig.…”

“…An experimental study by Saha et al [10] showed that methanol and water should be the first consideration when choosing a working fluid for open loop OHP with vertical and horizontal orientation. Several visual studies have been conducted by various researchers that successfully characterized at least five different flow patterns [2,9,[11][12][13][14][15][16]. The results were dispersed bubble, vapor plug, long vapor plug, semi-annular flow and annular flow.…”

A Deep Learning Model for Predictive Maintenance in Cyber-Physical Production Systems Using LSTM Autoencoders

“…These data values were processed as time-series data because tools like Discrete Wavelet Transform (DWT) and Fast Fourier Transform (FFT) have not been preferred for this case. From our analysis of the data, the oscillating components likely will not reveal any regular behavior in terms of frequency because the oscillations of the features used, the temperature, and the hydraulic force did not appear to present any periodicity [ 56 ].…”

Investigação teórica-experimental do desempenho térmico de tubos de calor pulsantes poliméricos

“…Os autores concluíram que, mesmo que o tubo de calor pulsante tenha uma geometria muito simples (apenas duas voltas), sua condutividade térmica efetiva em geral pode atingir quase 6000 W/m.K, considerado um valor impressionante para muitas aplicações práticas. Karthikeyan et al (2015) utilizando tubo de vidro de diâmetro interno igual a 2,5 mm e externo igual a 6,0 mm, com 5 voltas e água deionizada como fluido de trabalho, com fração de enchimento igual a 50%, obtiveram a condutividade térmica efetiva nas posições vertical assistida pela gravidade(+90 • ) e na horizontal(0 • ). Os resultados apresentaram condutividade térmica efetiva variando na faixa de 80 a 320 W/m.K para potência de entrada variando de 10 a 110 W na posição vertical assistida pela gravidade(+90 • ).…”

“…Na Fig. 47c Fonte: Adaptada de Xian et al (2014, p.338) Os padrões de escoamento pistonado e semi-anular foram obtidos no trabalho Karthikeyan et al (2015). O tubo de calor pulsante de vidro, diâmetro interno igual a 2,6 mm, água e nano partículas de óxido de cobre CuO com fração de enchimento igual a 50% e 5 voltas, foi utilizado no experimento na posição vertical assistida pela gravidade(+90 • ) e na horizontal(0 • ).…”