He II Heat transfer through a Corrugated Tube -Test Report (original) (raw)
Related papers
Journal of Applied Mechanical Engineering, 2012
Estimating the feasibility of intensifying thermal mechanisms in MSF plant is investigated by employing Enhanced Tubing Test Apparatus for heat transfer characterization with conventional type. Utilizing actual Brine water, study the influence of flow speeds on fouling pattern and the effect of tube diameter on its behaviour. Experimental results are discussed for both smooth and corrugated tube, when applying fresh and real brine water on different tube diameters 19.05, 23 and 29.5, on flow speeds 0.1, 0.1645 and 0.2398 m/s. Apparatus (A) has to be redesigned, since problems were developed through its components. Difficulties revealed with former test-rig, are given a careful consideration in assembly of a new one. The modified setup facilities included a new configured design for the steam condenser, equipped in such a way to minimize mentioned obstacles, dismantling faced problems associated with; circulated pumps, boiler, flow meters and its place of fitting, careful identifying the tested tube characteristics, a wise differentiation between properties of brine and fresh water, a creation of uniform steam temperature distribution inside the rig, preventing a creation of two phase flow and simulating the actual circumstances in real desalination platform. The continuous experimental running hours used by this designed test-rig(B) is 160 hrs. Use is made of two horizontally mounted tubes through which the coolant solution is flowing. Corrugated and smooth tubes are examined at a time to unify the tested conditions on both. The study is carried-out for two different coolants, fresh and brine water. Examining effect of fouling on both corrugated and smooth tube, changing tube diameters and coolant flow speeds on experimental data. Results are provided in the form of: overall heat transfer coefficient with fresh and brine water vs. time for both tubes on different flow speeds, overall heat transfer coefficient with brine water vs. time for both tubes on a critical coolant flow speed with various chosen tube diameters, asymptotic values of overall heat transfer coefficient with fresh water vs. tube diameters for both corrugated and smooth on a critical flow speed, asymptotic values of overall heat transfer coefficient with brine water vs. coolant flow speeds for both corrugated and smooth with a chosen critical tube diameter and the tube fouling resistance vs. time, using tube diameter 23 mm and coolant flow velocity 0.1 m/s. On global look this study is significant to provide a useful correlation; as the studied tube diameter increased; with increasing flow speed expectation is for achieving a higher value of asymptotic overall heat transfer coefficient.
Experimental measurements of heat transfer in an internally finned tube
1998
This paper reports new experimental data for turbulent fluid flow and heat transfer in a tube having internal fins. An experimental setup was designed to study the heat transfer performance in the entrance region as weg as in the fully-developed region. The tube and the fin assembly was cast from aluminum to avoid any thermal contact resistance. The length of the test section was 15.2 m. The inner diameter of the tube was 70 nun. The tube contained six equally spaced fins of height 15 mm. Air was used as the working fluid in all experiments. The Reynolds number based on hydraulic diameter ranged from 2.6x104 to 7.9x10 4. Heat was supplied from an electrical heating system providing an uniform heat flux around the tube periphery over the entire length of the test section. Results exhibited high pressure gradients and high heat transfer coefficients in the entrance region, approaching the fully developed values away from the entrance section. Nusselt numbers of the finned tube were compared with those for an unfinned (smooth) tube for both constant Reynolds number and constant pumping power. The enhancement of heat transfer rate due to integral fins was found to be very significant over the entire range of flow rates studied in this experiment. Heat transfer coefficient, based on inside diameter and nominal area of finned tube exceeded unfinned tube values by as much as 112%. When compared at constant pumping power, an improvement as high as 52% was observed for the overall heat transfer rate. The results of this study indicates that significant enlaancement of heat transfer is possible by using internal fins without sacrificing any additional pumping power. The experimental results are expected to be very useful for the design of pipelines and heat exchanger tubes.
COMPARISON OF OVERALL HEAT TRANSFER COEFFICIENT IN PLAIN AND CORRUGATED PIPE AND IT'S CFD ANALYSIS
Shell and tube heat exchangers are used for convective heat transfer between two fluids, where one fluid flows through the tubes and other flows in the shell. Smooth pipes are usually used in shell and tube heat exchangers. Corrugated pipe provides more heat transfer as it increases the surface area and turbulence of fluid and hence increases the effectiveness of heat exchanger. Experiments have been carried out on plain pipe and corrugated pipe to determine overall heat transfer coefficient. Experimental results of the experiments performed on a smooth pipe and corrugated pipe have been compared using CFD analysis for the same conditions. Numerical analysis on plain and corrugated pipes has been performed using ANSYS FLUENT.
Heat Transfer Analysis Through Corrugated Twisted Pipe
In this paper the Study of transient heat transfer in double tube heat exchanger has enhanced. The inner tube of the setup was made with corrugation on both inner and outer walls by twisting the pipe from one end, which gives the more swirling motion to the fluid particles flowing over it. The flow inside the pipe was considered as turbulent, and the analysis was done experimentally and theoretically by using the ANSYS workbench. The experimental results were compared with the experimental values taken in the setup done by considering the inner tube as normal pipe. In both heat exchangers the values were taken and compared with the theoretical analysis. Temperature distribution and heat transfer rate were calculated and the details of the study have been discussed in this paper.
THERMAL PERFORMANCE TESTING OF CRYOGENIC PIPING SYSTEMS
International Congress of Refrigeration, 2004
Thermal performance measurement of piping systems under actual field conditions is important for space launch development and commercial industry. Knowledge of the true insulating effectiveness is needed in system design, development, and research activities. A new 18-meter-long test apparatus for cryogenic pipelines has been developed. Three different pipelines, rigid or flexible, can be tested simultaneously. Critical factors in heat leak measurements include eliminating heat transfer at end connections and obtaining proper liquid saturation condition. Effects resulting from variations in the external ambient conditions, like wind, humidity, and solar radiation, must be minimized. The static method of liquid nitrogen evaporation has been demonstrated, but the appartus can be adapted for dynamic testing with cryogens, chilled water, or other working fluids. This technology is suited for the development of an industry-standard test apparatus and method. Examples of the heat transfer data from testing commercially available pipelines are given. Prototype pipelines are currently being tested and evaluated at the
EXPERIMENTAL STUDY ON THE ANALYSIS OF HEAT ENHANCEMENT IN CORRUGATED TWISTED PIPES
In heat exchanger, the enthalpy is transferred between two or more fluids, at different temperatures. The major challenge in designing a heat exchanger is to make the equipment more compact and achieve a high heat transfer rate using minimum pumping power. In recent years, the high cost of energy and material has resulted in an increased effort aimed at producing more efficient heat exchange equipment. Furthermore, as a heat exchanger becomes older, the resistance to heat transfer increases owing to fouling or scaling. The heat transfer rate can be improved by introducing a disturbance in the fluid flow thereby breaking the viscous and thermal boundary layer. However, in the process pumping power may increase significantly and ultimately the pumping cost becomes high. Therefore, to achieve a desired heat transfer rate in an existing heat exchanger at an economic pumping power, several techniques have been proposed in recent years and are discussed under the classification section. In this work, a study of transient heat transfer in double tube heat exchanger has enhanced. The inner tube of the setup was made with corrugation on both inner and outer walls by twisting the pipe from one end, which gives the more swirling motion to the fluid particles flowing over it. The flow inside the pipe was considered as turbulent, and the analysis was done experimentally and theoretically by using the ANSYS workbench. The experimental results were compared with the experimental values taken in the setup done by considering the inner tube as normal pipe. In both heat exchangers the values were taken and compared with the theoretical analysis. Temperature distribution and heat transfer rate were calculated and the details of the study have been discussed in this paper.
Test methodologies for determining high temperature material properties of thin walled tubes
2017
This publication is a Technical report by the Joint Research Centre (JRC), the European Commission's science and knowledge service. It aims to provide evidence-based scientific support to the European policymaking process. The scientific output expressed does not imply a policy position of the European Commission. Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use that might be made of this publication.
Heat Transfer Enhancement in Corrugated Pipes
Proceedings of the International Heat Transfer Conference; Paper No. IHTC14-23225 - August 8-13, 2010, Washington, DC, USA, 2010
ABSTRACT: The temperature distribution and heat transfer coefficient are investigated in forced convection with Newtonian fluids in pressure gradient driven hydrodynamically and thermally fully developed steady laminar flow in transversally corrugated pipes. The governing equations are solved by means of the epitrochoid conformal mapping and exact analytical solutions are derived for the velocity and temperature fields without viscous dissipation. The effect of the corrugations and the number of waves on the friction factor, the temperature distribution and the heat transfer enhancement is discussed.