82 results about "Blackbody cavity" patented technology

A silicon carbide ceramic foam solar energy air heat absorber uses silicon carbide ceramic foam materials as solar energy absorber. The silicon carbide ceramic foam absorber is wrapped with an insulating layer (2). A radiant heat flux (3) projects onto the surface of the silicon carbide ceramic foam absorber (1) or into an artificial blackbody cavity (9) and is received by the silicon carbide ceramic foam absorber (1). Cold air (4) flows in from the side of the silicon carbide ceramic foam absorber (1) positive to the radiant heat flux (3). Hot air (5) is obtained through heat exchange of thecold air and the radiant heat flux. Or the cold air (4) flows in from the side of the silicon carbide ceramic foam absorber (1) positive to the radiant heat flux (3) or back to the radiant heat flux (3). The hot air (5) of 700 to 1300 DEG C is obtained through the heat exchange of the cold air and the radiant heat flux through a quartz window (10). The silicon carbide ceramic foam absorber (1) buries an air diversion channel (8) beforehand. The invention can effectively receive radiant heat and emit heat to the air and take advantage of self-sensible heat to store heat at the same time.

A blackbody cavity having two types of wall surfaces wherein a first type has high emissivity and a second type has low emissivity. The low emissivity wall surface has an aperture from where the infrared radiation escapes the cavity, and is preferably shaped to minimize the escape through the aperture of radiation emanated directly from the low emissivity wall itself. The combination of high and low emissivity wall surfaces allows the blackbody to reduce the influence of the environmental temperature while maintaining emissivity approaching unity.

A blackbody cavity having two types of wall surfaces wherein a first type has high emissivity and a second type has low emissivity. The low emissivity wall surface has an aperture from where the infrared radiation escapes the cavity, and is preferably shaped to minimize the escape through the aperture of radiation emanated directly from the low emissivity wall itself. The combination of high and low emissivity wall surfaces allows the blackbody to reduce the influence of the environmental temperature while maintaining emissivity approaching unity.

A device (10) for calibrating tympanic thermometers includes an enclosure (12) which may be heated or cooled depending upon the testing temperature. Within the enclosure (12) there is provided a sealed flask (14) which contains substance (16) which melts at the test temperature (this may be ethylene carbonate, melting point 36.3° C.). Located within the sealed flask (14) is a re-entrant well (18) which provides the blackbody for testing tympanic thermometers and a viewing aperture (20). The well (18) is treated to achieve a high surface emissivity. The device (10) allows the testing of thermometers by measuring the triple point or melting point of the substance (16). As the temperature of the substance (16) is accurately known, so is the temperature in the blackbody cavity (18) and thermometers can be calibrated thereby.

The invention provides a method and system for measuring emissivity of a high-temperature material, wherein the system comprises a large-power radiation source, a beam expanding, reshaping and homogenizing device, a vacuum chamber, a sample test platform, a rotating planar reflector, a micro-imaging device, a light spectrum switching device, a radiation energy imaging measuring device, and a temperature measuring device. According to the method and the system provided by the invention, a blackbody cavity is machined out on a tested sample; an imaging method is used to simultaneously measure a radiation energy of a tested material surface and the blackbody cavity; a narrow band filter is employed for performing light spectrum selection, so that not only can a tested material and a standard reference sample be simultaneously measured, but also the sample and a reference source can be guaranteed to be completely isothermal, and therefore, an error resource of emissivity measurement can be remarkably reduced, measurement accuracy and test convenience can be improved, and engineering application is facilitated.

A solar absorber for a concentrated solar power (CSP) dish system includes a cylindrically shaped blackbody cavity receiver fused to a cylindrically shaped heat exchanger shell covering the receiver to form a monolithic cavity receiver and heat exchanger. An exterior surface of the cavity receiver has grooves embedded to create a duct spiraling about the exterior of the cavity receiver so that the duct forms tubes of a tube-style heat exchanger when covered by the heat exchanger shell. An interior diameter of the cavity receiver is greater than or equal to a diameter of an aperture of the cavity receiver, and a longitudinal interior depth of the cavity is greater than or equal to twice the interior diameter of the cavity receiver. The monolithic solar absorber is preferably composed of a ceramic material such as silicon carbide having emissivity greater than 0.9.

The invention discloses a sapphire optical fiber blackbody cavity high-temperature sensor and a temperature measurement method thereof, and is applicable to the field of high-temperature measurement. The sensor comprises a sapphire optical fiber blackbody cavity sensing head, an energy transmitting optical fiber, a photoelectric detector, a pre-amplifying module, an AD sampling module, a signal processing module and a display module. A sapphire optical fiber blackbody cavity has the radiation characteristic approximate to that of an ideal blackbody, thermal radiation energy of a temperature field can be transmitted to the photoelectric detector by the energy transmitting optical fiber to be converted into an electric signal, the electric signal is acquired by the AD sampling module, the signal processing module analyzes and calculates a sampled digital signal, and finally, by data fitting and calibration, a corresponding function relationship between a temperature and the electric signal is obtained so as to implement measurement on the temperature. The sapphire optical fiber blackbody cavity high-temperature sensor disclosed by the invention is simple in system structure and convenient to use.

The invention discloses a sample heating device used in integrating-sphere reflectivity measurement. The sample heating device comprises a copper bar, a heat-insulating ceramic shell, a resistance wire, a temperature controller and a K-type thermocouple, wherein, the copper bar is wrapped with an insulating material and then wound with the resistance wire, and the resistance wire is connected with a resistance regulator in series and then is connected with the temperature controller; one side of the copper bar is used for fixing a ceramic tube sleeve, high-emissivity coating is coated on one side of the copper bar and all over the ceramic tube sleeve to obtain a blackbody cavity, and a test sample is heated by radiation of the blackbody cavity; the test sample is fixed at the other side of the ceramic tube sleeve; the K-type thermocouple is fixed on a vertical side surface of the test sample and is taken as a temperature sensor to be connected with the temperature controller so as to regulate and control the heating time of the resistance wire; and the heat-insulating ceramic shell is fixed outside the whole heating device. The sample heating device has the beneficial effects thatthe sample can be stably heated in reflectivity measurement, the problem that the existing integrating-sphere reflectivity test device can only test the sample at room temperature is solved, and the heat-insulating ceramic shell plays a role in protecting the integrating-sphere reflectivity test device.

The invention discloses a portable blackbody metering furnace based on a semiconductor and a mini-sized water cooling and heat radiation technology. The furnace includes a blackbody cavity of which one end is provided with a uniform temperature block. The uniform temperature block is provided with a temperature sensor at the center position inside the uniform temperature block. Outside the blackbody cavity, a surface of the uniform temperature block is closely adhered to a semiconductor sheet. A surface of the semiconductor sheet is closed adhered to a heat radiation system. Inside the blackbody cavity, a surface of the uniform temperature block is subject to rough treatment and assumes a rough surface, and is also subject to blackening treatment. The blackbody cavity is provided with a nitrogen purging element therein. An external circumference of the blackbody cavity is wrapped with a heat-insulation layer. The furnace also includes a PCB temperature control circuit which is intended for regulating heating or cooling of the semiconductor sheet based on an output of a temperature control instrument. The furnace provides a comparatively stable calibration source for a medium and low temperature infrared thermometric indicator on an industrial site to conduct accurate calibration. The furnace is easy to carry out and fast in temperature increasing and decreasing rate, and can greatly increase calibration efficiency of a radiation thermometer.

The invention discloses a high temperature photoelectric temperature measuring system. The high temperature photoelectric temperature measuring system comprises a blackbody cavity, a high temperature optical fiber, a low temperature optical fiber, an optical coupler which is used for connecting the high temperature optical fiber and the low temperature optical fiber, a battery of lens which is arranged at an exit end of the low temperature optical fiber and used for conducting collimation to measured emitted light, a light filter which is arranged on the back of the battery of lens in a parallel mode, a photoelectric detector which is used for converting optical signals which are filtered by the light filter into electrical signals, a signal processing system which is connected with the photoelectric detector and used for analyzing and processing the electrical signals and a display unit which is connected with the signal processing system. The high temperature optical fiber is connected with the blackbody cavity, the battery of lens, the light filter, the photoelectric detector, the signal processing system and the display unit are sequentially distributed on the same straight line from left to right, and the photoelectric detector and the display unit are both connected with the signal processing system. The high temperature photoelectric temperature measuring system is simple in structure, convenient to operate, high in temperature measuring precision, reliable in performance, long in service life, low in cost, and capable of replacing the application and the production of a traditional platinum-rhodium thermocouple.

A thermopile, utilizing the Seebeck effect, is placed into a blackbody cavity or other ambient heat source, where the hot junctions are inside the heat source, and the cold junctions are outside the heat source, and thereby produces a voltage.

The invention discloses a groove type solar heat collector in order to overcome the defects that traditional groove type system solar vacuum heat collecting pipes are large in machining and manufacturing difficulty, short in service life and high in manufacturing and maintenance cost. The groove type solar heat collector comprises a heat collecting pipe, a condenser and a bracket. The heat collecting pipe comprises a glass round pipe, an absorbing coating, a heat preservation layer and a heat absorbing working medium. The absorbing coating is arranged on the inner wall of the glass round pipe. The heat preservation layer is arranged on the outer wall of the glass round pipe. A heat preservation layer arc-shaped opening is formed in the heat preservation layer. An absorbing coating arc-shaped opening is formed in the position, corresponding to the heat preservation layer arc-shaped opening, of the absorbing coating. The glass round pipe is filled with the heat absorbing working medium. Furthermore, a low-radiation film is further arranged between the glass round pipe and the heat preservation layer. By means of the groove type solar heat collector of the structure, the characteristic that a blackbody cavity is high in absorption rate can be fully utilized, and the heat collecting efficiency is greatly improved; meanwhile, the defect that the requirement for vacuum of traditional vacuum pipes is rigorous can further be overcome; and the groove type solar heat collector has the advantages of being simple in structure, convenient to maintain, low in manufacturing cost and the like.

The invention relates to an absolute radiation heat flow meter calibration method, and belongs to the thermal technical field. The absolute radiation heat flow meter calibration method includes: enabling a radiation heat flow meter to penetrate into a blackbody cavity of a blackbody radiation source; calculating and evaluating effective emissivity of an equivalent cavity model formed by the radiation heat flow meter and the blackbody cavity of the blackbody radiation source through Monte Carlo arithmetic; thereby using temperature value of the blackbody cavity of the blackbody radiation source to figure out standard radiation heat flow value through the Stephen-Boltzmann law, and achieving absolute calibration for the radiation heat flow meter. The absolute radiation heat flow meter calibration method comprehensively considers a wall temperature gradient of the blackbody cavity of the blackbody radiation source in computational analysis of the effective emissivity of the equivalent cavity model, and confirms the best position of the radiation heat flow meter deeply into the blackbody cavity of the blackbody radiation source so as to obtain the maximum effective emissivity of the equivalent cavity model. The absolute radiation heat flow meter calibration method is directly, small in number of middle links, small in uncertainty of measurement, and suitable for the absolute radiation heat flow meter calibration which is traceable to temperature.

The invention relate to the field of optical radiation measurement, in particular to a blackbody cavity of a low-temperature radiometer. The blackbody cavity comprises a cavity body formed by a regular cone side face (6), a cylinder side face (5) and an oblique bottom face (4). The axes (3) of the regular cone and the cylinder coincide with each other. An included angle (1) is formed between a generatrix of the regular cone and the axis of the regular cone. A cavity incidence bore (7) is formed in the thin end of the regular cone. The plane where the cavity incidence bore (7) is located is perpendicular to the axis (3) of the regular cone. An included angle (2) is formed between the oblique bottom face (4) and the axis of the cylinder. According to the invention, by adopting a cavity body structure combining the oblique bottom, the cylinder and the cone, through the conical light shielding design, stray light outside the cavity body can be blocked and reflection light in the cavity body are prevented from overflowing the cavity body; and the coating layer of the inner wall of the cavity body is made of pure specular reflection graphene materials, so diffusion reflection of light radiation in the cavity can be reduced; temperature distribution is relatively centralized; and temperature response speed is fast.

The present invention relates to an inner cone type temperature equalizing target heat pipe blackbody and belongs to the radiation temperature measurement technical field. According to the device, a blackbody cavity (7) and a heat pipe (5) are designed integrally, so that heat conduction loss between the heat pipe and the blackbody cavity can be decreased, and therefore, heating efficiency and a temperature rise rate can be improved; an inner cone type temperature equalizing target (4) is arranged at the bottom of the blackbody cavity (7), and a distance between a standard thermocouple and the surface of the target is made as small as possible, so that the accuracy of the temperature of the surface of the target can be ensured; the inner cone type temperature equalizing target can assist in increasing the insertion depth of the standard thermocouple or a platinum resistor, so that heat conduction error can be decreased; and the heat pipe (5) adopts three-section heating, and the temperature sensor (1) of each section of the heat pipe (5) is installed on the external wall surface of the heat pipe, and two sections of the heat pipe wrap the exterior of the cylinder of the heat pipe, and the third section is a heating disc and is arranged at the bottom of the heat pipe, and the temperature of the three sections is adjusted respectively, so that the uniformity of the axial temperature field of the blackbody cavity can be guaranteed. Compared with the prior art, the inner cone type temperature equalizing target heat pipe blackbody of the invention has the advantages of high temperature uniformity and high accuracy.

The invention provides a temperature sensing device. The temperature sensing device comprises a sensing head base, a sensing head body part, a simulated blackbody cavity, a high-temperature optical system, a high-temperature-resistant optical fiber, an optical fiber fixing structure, a fixing jackscrew, a light transmission optical fiber and a signal processing system. The simulated blackbody cavity is arranged in the sensing head base; the high-temperature optical system is used for collecting an optical radiation signal emitted by the simulated blackbody cavity; the high-temperature-resistant optical fiber is used for receiving the optical radiation signal collected by the high-temperature optical system; the optical fiber fixing structure is used for fixing the high-temperature-resistant optical fiber; the fixing jackscrew is used for limiting movement of the optical fiber fixing structure in the axial direction of the sensing head body part; the light transmission optical fiber isconnected with the high-temperature-resistant optical fiber; and the signal processing system is used for converting the optical radiation signal outputted by the light transmission optical fiber intothe temperature of an object to be measured. According to the technical scheme, the technical problems that in the prior art, the temperature measuring range of a temperature sensing device is limited, and dynamic response, interference shielding, service life and severe environment adaptability are poor are solved.

The invention provides a probe temperature-sensing blackbody cavity for a sapphire optical fiber temperature sensor, wherein the inner structure of the temperature-sensing blackbody cavity is in a box type structure; the bottom of the temperature-sensing blackbody cavity is semi-spherical, and the upper end of the temperature-sensing blackbody cavity is cylinder-shaped; an internal thread is processed at the opening of the temperature-sensing blackbody cavity; the rear end of the temperature-sensing blackbody cavity is provided with a circular light blocking sheet with a radiation adjusting hole. The blackbody cavity disclosed by the invention is prepared from a zirconium boride ceramic material with the melting point of more than 3000 DEG C. The radiation signals of the blackbody cavity are stable in feature, and are easy for sapphire optical fibers to receive and transmit, thus stable whole performance of the sensor is ensured.

The invention discloses an infrared ear thermometer calibration device and method based on a three-cavity blackbody radiation source. The device includes a single-chip microcomputer main control module, a temperature display module, a temperature setting module, a first blackbody radiation source, and a second blackbody radiation source and the third blackbody radiation source; the three blackbody radiation sources are identical in structure, and each blackbody radiation source includes a thyristor, an A / D conversion circuit, a protection circuit, a thermal insulation module, a heating module, a temperature sensor module and a blackbody space cavity. The invention uses a relatively simple calibration device, which is easy to operate, makes the calibration of the infrared ear thermometer more convenient and fast, the operation process is simpler, and the cost performance is high, providing corresponding technical guarantee for the calibration of the infrared ear thermometer.

The invention discloses an ultra-high temperature material spectral emissivity measuring system and a using method thereof. The measuring system comprises an infrared spectrum radiation measuring device, a computer control system, a blackbody radiation source, a temperature control system and an auxiliary optical path system. A sample slot and a blackbody cavity hole are arranged on the temperature control system, and a sample in the sample slot is heated to a set temperature. The computer control system controls the auxiliary optical path system, the radiation of the sample and the radiationof the blackbody radiation source placed in the blackbody cavity hole at that time are reflected to the infrared spectrum radiation measuring device, the radiation measurement is carried out, and thespectral emissivity of the sample is calculated and obtained through the computer control system. The spectral emissivity measurement of an ultra-high temperature material can be achieved through integrated design, and at the same time, the measurement accuracy of the spectral emissivity of the measured sample can be greatly improved by using the technology of reducing background radiation.

The invention discloses a ceramic sheath of a fiber high temperature detector, and belongs to the technical field of temperature detection. A sapphire fiber in which a temperature sensitive blackbody cavity is sputtered at the end portion and a ceramic sheath are included, the sapphire fiber penetrates into a fiber hole of the ceramic sheath, the diameter of the fiber hole matches that of the sapphire fiber, one end of the ceramic sheath is provided with a protective chamber, and one end of the blackbody cavity of the sapphire fiber is placed in the protective chamber. According to the invention, the blackbody cavity of the sapphire fiber is arranged in the protective cavity of the ceramic sheath, protection requirements are met, the blackbody cavity of the sapphire fiber makes full contact with a measured medium, and the instantaneity and accuracy of measurement are ensured; a fiber butt-joint structure is arranged in the sheath to reduce the utilization amount of the sapphire fiber and the manufacture cost; and the ceramic sheath is simple in structure, easy to prepare and suitable for batch production.

The invention relates to a method for designing a graphite blackbody cavity of a high-temperature blackbody radiation source, and belongs to the technical field of thermology. The method comprises the steps as follows: in the aspect of conical end part design of the graphite blackbody cavity, the radiation heat exchange angle factor theory is taken as an analysis tool, the hypothesis that the inner wall surface of the end part of the graphite blackbody cavity and the inner wall surface (including the bottom surface) of the cavity are consistent during radiation heat exchange is proposed, and then relative parameters of cone of the end part of the graphite blackbody cavity are calculated and inferred. The method is practicable in principle, reasonable in hypothesis, good in practice effect and applicable to the design of the graphite blackbody cavity of the high-temperature blackbody radiation source.

The invention discloses a three-cavity blackbody radiation source for measuring emissivity. The three-cavity blackbody radiation source comprises a liquid thermostat for holding a liquid medium inside, blackbody cavity shells, a temperature control device and a standard thermometer; the number of the blackbody cavity shells is three; the blackbody cavity shells consists of cavities with conical front ends and cylindrical rear ends; the internal walls of the blackbody cavity shells are coated with coatings of high-emissivity painting; the liquid thermostat is internally provided with the temperature control device, and three grooves which are conical at the front ends and cylindrical at the rear ends are in equal intervals and in the same size; three blackbody cavity shells are respectively arranged in the grooves which are the same with the blackbody cavity shells in shape; the external side of the liquid thermostat is fixedly connected with the external cylindrical surfaces of the cylindrical cavities with three openings; and the standard thermometer is arranged in the liquid thermostat. According to the three-cavity blackbody radiation source for measuring emissivity, the number of the blackbody cavities is increased, and the emissivity of three different samples to be measured can be measured at the same time; the data of the sample to be measured, a standard sample and a radiation source can be timely contrasted. And the blackbody cavities can be detached and are convenient to place samples.

An embodiment of the invention discloses a measurement method on the basis of PI (proportion and integration) controllers for solar absolute radiometers. The measurement method includes acquiring temperature step response curves of blackbody cavities and building mathematical models of the blackbody cavities; simulating and optimizing parameters of the PI controllers by the aid of simulation software; regulating electric power of the blackbody cavities by the aid of the PI controllers at radiation observation stages until cavity temperatures return heat balance states by means of regulation soas to obtain first balance temperatures and compensation electric power; regulating the electric power of the blackbody cavities by the aid of the PI controller at electric calibration stages until the cavity temperatures return the heat balance states by means of regulation so as to obtain second balance temperatures and calibration electric power. The measurement method has the advantages thatthe electric power of the blackbody cavities is regulated by the aid of the PI controllers, accordingly, the regulation time of shutter on-off moments can be shortened, the measurement periods of total solar irradiance monitoring instruments can be shortened, and the problem of deterioration of measurement accuracy of measurement calculation formulas due to photoelectric non-equivalence of the traditional measurement methods can be solved.

The invention discloses a black body and sample integrated heating apparatus and a black body and sample integrated heating method for spectrum emissivity measurement. According to the present invention, a high-purity metal tungsten tube is adopted as a heating body and a corundum tube is adopted as a heat conductor and an insulator to transfer heat to a graphite tube wall and a graphite substrate so as to form a black body isothermal cavity; the graphite substrate adopted as the black body cavity bottom is the heat conductor during a sample heating process so as to heat a sample to the same temperature as the black body; the black body and sample integrated heating apparatus uses a set of a heating and temperature control unit to synchronously heat the black body and the sample so as to ensure the uniformity of the temperatures of the black body and the sample; and the apparatus has advantages of high measurement result accuracy, good repeatability, compact structure and low cost in the spectrum emissivity measurement system.

The invention discloses a two-stage parabolic type slot solar energy concentrating system provided with a blackbody cavity with a converging function. The solar energy concentrating system mainly comprises two components, namely, a reflecting mirror and a hollow cavity type evacuated collector tube group, wherein the reflecting mirror comprises a main reflecting mirror and an auxiliary reflecting mirror; the main reflecting mirror and the auxiliary reflecting mirror are connected through a support, the main reflecting mirror is integrally formed, and converging surfaces of the main reflecting mirror and the auxiliary reflecting mirror are coated with a high reflectance coating; the hollow cavity type evacuated collector tube group consists of an artificial blackbody cavity casing provided with an entrance port, and a tubular heat absorber group; the artificial blackbody cavity casing is located between the main reflecting mirror and the auxiliary reflecting mirror; and a reflecting surface of the auxiliary reflecting mirror is an elliptical surface, an upper focus point of the elliptical surface is overlapped with a focus point of the main reflecting mirror, and a lower focus point of the elliptical surface is located in the central position of the artificial blackbody cavity casing. The two-stage parabolic type slot solar energy concentrating system overcomes the disadvantages that a one-stage parabolic type converging surface is low in strength, the processing technology is difficult, the mirror surface errors are large, the heat convection loss between an artificial blackbody cavity and the environment as well as between a tubular heat absorber and the environment is large, and the like.

The invention discloses sapphire temperature sensor and a manufacturing method thereof and a temperature measuring system. The sapphire temperature sensor comprises a heat protection device, a sapphire fiber-optics probe and an optical fiber coupler. One end of the sapphire fiber-optics probe is a sensing head, and the other end of the sapphire fiber-optics probe is connected with the optical fiber coupler. The heat protection device surrounds the outside of a sapphire optical fiber. The sensing head is arranged at one end of the heat protection device, and the other end of the heat protectiondevice is connected with the optical fiber coupler. The sensing head is formed by wrapping the outer surface of one end of the sapphire optical fiber by a blackbody cavity, and the blackbody cavity is formed by heating multiple kinds of temperature sensing material particles to a molten state through plasma electric arcs and evenly spraying the temperature sensing material particles to the outersurface of one end of the sapphire optical fiber. The sapphire optical fiber temperature sensor manufactured through a plasma spraying method has the advantages of being wide in temperature measuringrange, high in heat response speed, high in precision, long in service life, low in cost and essentially insulated, the advantages are more prominent than those of a traditional thermometer, and the corrosion resistance and the electromagnetic interference resisting capacity are high.

The invention discloses a normal temperature point source blackbody which belongs to the field of optical measurement. The normal temperature point source blackbody is technically characterized in that a number of annular drives which are composed of semiconductor refrigeration pieces and radiating pieces are arranged on the outer side wall of a multi prismatic blackbody cavity along the axial direction, so as to realize temperature control on the normal temperature point source blackbody; temperature sensors are uniformly distributed on three different axial positions on the side wall of the blackbody cavity, so that the overall temperature in the blackbody cavity can be accurately controlled; an arc-shaped air inlet and a radiating fan are respectively arranged on front and rear end faces of a chassis, so that an air circulating passage is formed with a void in the chassis; the uniformity of the temperature in the blackbody cavity is ensured; the emission rate of the normal temperature point source blackbody provided by the invention can reach 0.998; the problem of a high emissivity blackbody radiation source required by field test and rapid measurement occasions is solved; and the normal temperature point source blackbody has the advantages of small volume, light weight, fast temperature fluctuation speed and portability.

A solar absorber for a concentrated solar power (CSP) system includes a cylindrically shaped blackbody cavity receiver fused to a cylindrically shaped heat exchanger shell covering the receiver to form a monolithic cavity receiver and heat exchanger. An exterior surface of the cavity receiver has grooves embedded to create a duct spiraling about the exterior of the cavity receiver so that the duct forms tubes of a tube-style heat exchanger when covered by the heat exchanger shell. An interior diameter of the cavity receiver is greater than or equal to a diameter of an aperture of the cavity receiver, and a longitudinal interior depth of the cavity is greater than or equal to twice the interior diameter of the cavity receiver. The monolithic solar absorber is preferably composed of a ceramic material such as silicon carbide having emissivity greater than 0.9.

The invention relates to a high-precision blackbody cavity in the field of optical radiation measurement. The high-precision blackbody cavity comprises a first cavity and a second cone. The first cavity comprises a cylindrical section and a conical section, the cylindrical section and the conical section are connected to form an open cavity structure, the conical section is of a frustum structure,and a notch is formed in the end of the conical section. The second cone is connected with the conical section through the notch, and the tip end of the second cone is located in a cavity of the conical section. The invention further provides a manufacturing method of the high-precision blackbody cavity. Through the combination of a regular conical surface and an inverted conical surface, the number of times of surface reflection or incident light absorption can be effectively increased, so that the absorptivity of the blackbody cavity is improved.