&ldquo;IIT Jodhpur is committed to impart quality education to facilitate the creation of qualified, competent and responsible human resources to meet the emerging technological challenges of the world. It is working towards creating an equitable learning platform that is positive, accessible and effective in the face of the modern societal and scientific advancements.

Flexibility in curriculum, in all its academic programs, encompassing elements of teaching, research, creativity, innovation and entrepreneurship is the most unique feature of IIT Jodhpur. The Department of Science and Technology (DST), under the National Mission on Cyber Physical Systems, has identified IIT Jodhpur as a Technology &amp; Innovation Hub in the area of Augmented Reality and Virtual Reality. The institute has also been nominated as the coordinator for the Jodhpur City and Knowledge Cluster by the Office of Principal Scientific Adviser, Government of India.

The sprawling 852-acre IIT Jodhpur campus is a majestic tribute to the deep-rooted diverse cultural heritage of the region. The campus is an architectural masterpiece, which is slated to become an international exemplar of sustainability with net-zero energy, and advanced water and waste management strategies.&rdquo;

IIT Jodhpur

The objective of the present work is to measure the heat transfer and pressure drop in flow boiling with refrigerant R123 as the working medium. Local heat transfer coefficient along the axial length of tube and overall averaged heat transfer coefficient are compared with available correlations. In the present study, spatial variation in heat transfer coefficient along the axial length of tube is analysed with the increase of quality. Variation in heat transfer coefficient in different flow boiling region i.e. subcooled, nucleate and convective is studied. The experiments are conducted with seven test sections made of SS304 having four different tube diameters 5.5 mm, 7.5 mm, 9.5 mm and 12.0 mm with two different heated lengths 500 mm and 1000 mm. The system pressure is varying from 1.3 bar to 3.2 bar. The experimental data of two-phase pressure drop and critical heat flux are compared with available correlations. Correlations are suggested to measure the local heat transfer coefficient during boiling process, two-phase pressure drop and critical heat flux. Data of critical heat flux are published to contribute in the data bank for horizontal straight tubes. © 2017 Elsevier Ltd

Department of Mechanical Engineering

World University root node

International Journal of Heat and Mass Transfer

Boiling pressure drop, local heat transfer distribution and critical heat flux in horizontal straight tubes

The objective of the present work is to investigate the heat transfer and pressure drop in flow boiling at low pressure with water as the working medium. The effect of pipe diameter, heat flux and mass flux on boiling pressure drop and local heat transfer coefficient is studied. In the present work, the available correlations are revisited for low pressure flow boiling. Comparison of local heat transfer coefficient with the existing correlation is carried out to identify an appropriate correlation which performs well in complete flow boiling range (subcooled regions and saturated regions) for water at low system pressure. Experiments are performed with eight test sections made of thin walled stainless steel (SS 304) tubes having inner diameters from 5.5 mm to 12 mm and length varying from 550 mm to 1000 mm. The system pressure is varying form 1 bar to 3 bar. No change in slope of heat transfer curve is found for subcooled regions. Heat transfer in all the three regions of subcooled boiling namely partial subcooled boiling, fully developed subcooled and net vapour generation are predicted by a single correlation. Tube diameter has no effect on boiling heat transfer distribution. However, tube diameter affects two phase pressure drop. Increase in mass flux increases the convective heat transfer coefficient. However, mass flux has no influence on subcooled and nucleate boiling heat transfer coefficient. Heat flux increases the boiling heat transfer coefficient. Increase in tube diameter and mass flux decreases the two-phase pressure drop. Most of all the correlations in the subcooled region predict heat transfer coefficient with reasonable accuracy. Kandlikar and Shah correlations perform well in the low pressure saturated boiling i.e. nucleate and convective. None of the available two-phase pressure drop correlations are able to predict the pressure drop in a low pressure system. A correlation is developed to predict two-phase pressure drop in low pressure flow boiling system with a reasonably good accuracy. © 2016 Elsevier Masson SAS

International Journal of Thermal Sciences

Boiling pressure drop and local heat transfer distribution of water in horizontal straight tubes at low pressure

The objective of the present work is to study the influence of curvature and Reynolds number on local heat transfer coefficient in a helical coil with water as the working medium. The local wall temperature is measured not only in the axial direction (along the length of coil) but also in the circumferential direction using infrared thermal imaging technique. The test sections are made of thin walled stainless steel (SS 304) tubes having an inner diameter varying from 5.4 to 7.5 mm with a thickness of 0.2 and 0.25 mm. The coil diameter to the tube diameter ratio ranges from 13.1 to 67 and coil pitch is 50 mm. The experimental results of friction factor and overall averaged total Nusselt number are compared with the available correlations in the literature. Correlations are suggested for overall averaged and local circumferentially averaged Nusselt number for inner side, outer side and total surface (inner side and outer side) of a helical coil. © 2015 Elsevier Ltd. All rights reserved.

Local heat transfer coefficient in helical coils with single phase flow

Abstract Capillary tubes are extensively used in several cooling applications like refrigeration, electronic cooling etc. Local pressure variation in adiabatic straight capillary tube (mini channel) is studied experimentally and numerically with R134a as the working fluid. Experiments are performed on two straight capillary tubes. It is found that the diameter is the most sensitive design parameter of the capillary tube. Experiments are performed on five helically coiled capillary tubes to quantify the effect of pitch and curvature of helically coiled capillary tube on the pressure drop. Non dimensionalized factor to account coiling of capillary tube is derived to calculate mass flow rate in helically coiled capillary tubes. Flow visualization in adiabatic capillary tube confirms the bubbly nature of two phase flow. Numerical and experimental investigations in diabatic capillary tube suggest that the use of positive displacement pump and choking at the exit of the channel ensures flow stability. © 2015 Elsevier Ltd.