Study Of Heat Transfer Characteristics Of Single-phase Fluid In Inclined Narrow Channel

Because of the narrow rectangular channel compact heat exchangers and design of largearea and flexible application of the unique characteristics of thermal hydraulics, reactor coredesign in recent years, the field of microelectronic systems used increasingly. Channelcross-section because of its specificity, the traditional empirical relation between the flow andheat transfer tube is not applicable, current research has focused on micro-channel,rectangular channel on heat transfer characteristics of the study also is based channel in avertical or heating under the state level, and tilt angle on the channel at different heat transfercharacteristics of the state is less, so the research angle of the narrow rectangular channel ofheat transfer fluid is necessary.Vertical and inclined thesis heated narrow rectangular channel under single-phase fluidwithin the heat transfer characteristics of experimental research, experimental refrigerant loopfluid flow for the forced circulation.Experimental tilt angle can be adjusted in the test rig to complete the experiment withinthe refrigerant circuit is de-ionized water, the stainless steel test section for the vertical narrowrectangular channels, respectively, vertical section of the test and the test section of the heattransfer characteristics of different tilt angle heat transfer characteristics during theexperimental studies, and experimental results of both were compared.The results show that angle of the narrow rectangular channels with no effect on heattransfer fluid. Laminar flow entrance section of the thermal boundary layer thinner, the heattransfer coefficient is higher than the fully developed, but the role of the fluid by buoyancy,causing the same to the convection, the flow of laminar flow occurs, reduce the heat transfercapacity, resulting in convection heat transfer coefficient decreases. In the fully developedlaminar flow, Re number from the number of affected tend to value, the formula predicted theexperimental error with Hartnett in between13.5%-16.8%; transitional and turbulent region,Re Nu number as the number of major factor, after the laminar flow breakdown point, reallyinto the fully developed turbulent flow areas, dramatically increase convection heat transfercoefficient, the experimental values calculated with the Dittus-Boelter formula for the errorbetween the value of25%or less.Inclined rectangular channel heat transfer characteristics of the narrow, narrow rectangular channel for the inclined state to provide a reliable basis for calculating heattransfer, laminar flow heat exchanger can be calculated by the formula Hartnett, turbulent heattransfer can be calculated by Dittus-Boelter formula.Numerical simulation of the heat transfer characteristics in the different aspect ratiochannel conditions and the introduction of secondary flow analysis in the simulation results.Found that the secondary flow channel shape and size, and fluid flow pattern in the channelwill affect the length ratio, there is no secondary flow phenomenon, along with thecross-sectional aspect ratio is shrinking, and the gradual emergence of the symmetry thesecondary flow vortex, the secondary flow, the length ratio to continue to reduce the flow butalso to stabilize the secondary flow disappears. Laminar flow conditions is more likely toproduce the phenomenon of secondary flow.