Discretization test method and device for impact jet enhanced heat exchange characteristics

Abstract

The invention provides a discretization test method for impact jet enhanced heat exchange characteristics, which comprises the following steps: designing a test device, arranging test cylinders below different positions of a heat exchange surface, discretizing a test object into test points, and performing an impact jet enhanced heat exchange experiment: moving an upper support plate of the test device together with the test cylinders upwards so that all parts of the test cylinder are higher than the heat insulation material and are in direct contact with the heating environment, and setting a baffle block between the upper support plate and the support sleeve, so that the upper support plate does not slide off in the heating process; placing the whole testing device in a heating furnace to be heated to the preset temperature; opening a furnace door, returning the upper support plate and the test cylinder in the furnace, quickly covering a heat insulation cover in the furnace, placing the test device at a corresponding position, removing the heat insulation cover at the upper part, quickly opening a jet flow valve, and recording the surface temperature; and calculating a convective heat transfer coefficient. The method is suitable for the discretization research of the heat exchange characteristic of the impact jet with large temperature difference and violent heat exchange.

Description

technical field [0001] The invention relates to the technical field of impingement jet heat and mass transfer research, in particular to a discretized test method and device for impinging jet enhanced heat transfer characteristics. Background technique [0002] Impingement jet enhanced heat transfer refers to the use of nozzles to spray a fluid with a certain pressure (gas, liquid, water mist, etc.) onto the heat transfer surface vertically or at a certain angle to achieve enhanced heating or cooling of the impact surface. The impinging jet generally has a large impact pressure, and the flow velocity of the fluid on the heat exchange surface is fast, and the boundary layer is thin, which can obtain a large heat exchange capacity, and is an extremely effective method of enhancing heat transfer. In addition, the impinging jet enhanced heat transfer has the characteristics of good controllability of heat transfer intensity (the cooling intensity can be effectively controlled by...

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Problems solved by technology

When there is a temperature gradient in the workpiece itself, the part with high heat temperature will inevitably transfer heat to the part with low temperature, which makes the test results unable to fully reflect the heat transfer capacity of the fluid, and to a certain extent depends on the material and size of the heat transfer object. All are related, leading to the existing transient experimental research on the same jet fluid condition, the same jet fluid condition, workpieces of different materials or workpieces with different thicknesses get different results

In addition, transient experiments generally require thermocouples to be installed inside the workpiece to measure the instantaneous temperature inside the workpiece. On the one hand, the machining error of the thermocouple embedded in the hole will affect the test results; on the other hand, the embedding of the thermocouple will also affect the material. The internal heat transfer law affects the experimental results; thirdly, the calculation process of the overall workpiece in the transient experiment needs to go through a complex two-dimensional or three-dimensional calculation process (such as the inverse heat transfer method to find the convective heat transfer coefficient), and the calculation amount is relatively large. Big

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