Test loop for simulating steam generator with or without axial economizer and test method thereof

A test method of a test loop for simulating a steam generator with or without an axial economizer, wherein the test loop for simulating the steam generator with or without the axial economizer comprises a cooling water loop, a water supply loop, a recirculated water loop and a power supply, wherein the cooling water loop is used for condensing and cooling wet steam and providing the wet steam to the water supply loop and the recirculated water loop, the water supply loop is configured for providing cold-state water to a test device for simulating the steam generator with or without an axial economizer, the recirculated water loop is configured for reheating cooled water to be saturated and providing the cooled water heated to the test device, the power supply is configured for supplying power to heating equipment in the test device, and the heating equipment in the test device comprises non-uniform heat flux electric heating rods which are divided into a left group and a right group and configured for simulating a hot side and a cold side of a U-shaped tube bundle in the steam generator;

• the cooling water loop comprises a second water tank, a cooling tower, a condenser, a second regulating valve, a third regulating valve and a first circulating pump, wherein an outlet of the second water tank communicates with the first circulating pump, an outlet of the first circulating pump communicates with a pipe side inlet of the condenser, a pipeline communicating with the first circulating pump and the condenser is provided with the second regulating valve, a pipe side outlet of the condenser communicates with an inlet of the cooling tower, and an outlet of the cooling tower communicates with an inlet of the second water tank;
• the water supply loop comprises a wet steam outlet, the condenser, a first water tank, a test section first inlet, a first regulating valve, a fourth regulating valve, a fifth regulating valve, a second circulating pump and a third circulating pump, wherein a shell side outlet of the condenser communicates with the second circulating pump, an outlet of the second circulating pump communicates with an inlet of the first water tank, a pipeline communicating with the second circulating pump and the first water tank is provided with the first regulating valve, an outlet of the first water tank communicates with the third circulating pump, an outlet of the third circulating pump communicates with the test section first inlet of the test device, a pipeline communicating with the third circulating pump and the test section first inlet is sequentially provided with a fifth regulating valve, a first thermometer, a first pressure meter and a second flow meter, the wet steam outlet in a top of the test device communicates with a shell side inlet of the condenser, and a pipeline communicating with the wet steam outlet and the condenser is provided with a third thermometer and a third pressure meter;
• the recirculated water loop comprises the wet steam outlet, the condenser, an electric heater, a test section second inlet, a seventh regulating valve and the second circulating pump, wherein a pipeline between the shell side outlet of the condenser and the second circulating pump is shared with the water supply loop, an outlet of the second circulating pump further communicates with an inlet of the electric heater, an outlet of the electric heater communicates with the test section second inlet of the test device, a pipeline between the outlet of the electric heater and the test section second inlet is sequentially provided with a first flow meter, the seventh regulating valve, a second thermometer, a second pressure meter and a third flow meter, and a pipeline between the wet steam outlet of the test device and the condenser is shared with the water supply loop;
• two branches are provided between the recirculated water loop and the water supply loop, one branch of the two branches is located between a pipeline from the first flow meter to the seventh regulating valve in the recirculated water loop and a pipeline from the fifth regulating valve to the first thermometer in the water supply loop, and the one branch is provided with a check valve;
• and another branch of the two branches is located between a pipeline from the seventh regulating valve to the second thermometer in the recirculated water loop and a pipeline from the second flow meter to the test section first inlet in the water supply loop, and the another branch is provided with an eighth regulating valve;
• wherein the test method comprises a first test method of the test loop for the steam generator with the axial economizer and a second test method of the test loop for the steam generator without the axial economizer;
• the first test method comprises following steps:
• under a condition that a central divider plate in the test device is not dismantled, taking the test device as a steam generator test device with the axial economizer;
• before a test, adding water to the first water tank and the second water tank to guarantee that the first water tank and the second water tank have enough air spaces for a pressure stabilizing effect, then opening all the regulating valves except bypasses, conducting a water adding and pressurizing test to guarantee that no leakage exists under pressure of the test loop;
• after pre-test work is done, closing the check valve and the eighth regulating valve to separate the water supply loop and the recirculated water loop, and after pressure relief, discharging water in the test device;
• fully opening the third regulating valve and the fourth regulating valve to keep the bypasses fully open;
• starting the third circulating pump, and regulating a flow of the fourth regulating valve and a flow of the fifth regulating valve, so that water can submerge the heating equipment in the test device;
• starting the first circulating pump, and regulating the third regulating valve and the second regulating valve to maintain a preset flow, so that the cooling water loop is put into operation;
• starting the heating equipment of the test device, and gradually increasing electric heating;
• after stable water flow exists at the outlet of the second circulating pump, starting the second circulating pump;
• regulating the seventh regulating valve, starting the electric heater;
• dividing half of condensed water, heating the condensed water to be saturated;
• and sending the condensed water heated, back to the test section second inlet to simulate the recirculated water in the steam generator;
• after all the equipment is put into operation and stably operates for a period of time, regulating the fifth regulating valve, so that a liquid level in downcomer section simulation pipes is stabilized under a working condition needing to be simulated;
• regulating the seventh regulating valve so that a flow in the recirculated water loop and a flow in the water supply loop are in a certain proportion, enabling a ratio of a recirculated water flow to a water supply flow to be (K−1):
• 1, wherein K is a circulation ratio in a simulated real steam generator, the recirculated water flow is flow measured by the first flow meter, and the water supply flow is flow measured by the second flow meter;
• regulating the eighth regulating valve so that the flow flowing into the test section first inlet through the eighth regulating valve accounts for 90% of a total flow of the recirculated water;
• and
• after the test loop operates in a steady state for 20 minutes, starting to record test data of pressures, flows and temperatures;
• and
• the second test method comprises following steps:
• before a test, under a condition that the central divider plate in the test device is dismantled, taking the test device as a steam generator test device without the axial economizer;
• adding water to the first water tank and the second water tank to guarantee that the first water tank and the second water tank have enough air spaces for a pressure stabilizing effect, then opening all the regulating valves except bypasses, conducting a water adding and pressurizing test to guarantee that no leakage exists under pressure of the test loop;
• after pre-test work is done, closing the seventh regulating valve, keeping the check valve and the eighth regulating valve open to combine the water supply loop and the recirculated water loop, and after pressure relief, discharging water in the test device;
• fully opening the third regulating valve and the fourth regulating valve to keep the bypasses fully open;
• starting the third circulating pump, and regulating a flow of the fourth regulating valve and a flow of the fifth regulating valve, so that water can submerge the heating equipment in the test device;
• starting the first circulating pump, and regulating the third regulating valve and the second regulating valve to maintain a preset flow, so that the cooling water loop is put into operation;
• starting the electric heating equipment of the test device, and gradually increasing electric heating;
• after stable water flow exists at the outlet of the second circulating pump starting the second circulating pump;
• regulating the seventh regulating valve, starting the electric heater, dividing half of condensed water, heating the condensed water to be saturated;
• and sending the condensed water heated, back to the test section second inlet to simulate the recirculated water in the steam generator;
• after all the equipment is put into operation and stably operates for a period of time, regulating the fifth regulating valve, so that the liquid level in the downcomer section simulation pipes is stabilized under a working condition needing to be simulated;
• regulating the check valve so that a flow in the recirculated water loop and a flow in the water supply loop are in a certain proportion, enabling a ratio of a recirculated water flow to a water supply flow to be (K−1):
• 1, wherein K is a circulation ratio in a simulated real steam generator, the recirculated water flow is flow measured by the first flow meter, and the water supply flow is flow measured by the second flow meter;
• and
• after the test loop operates in a steady state for 20 minutes, starting to record test data of pressures, flows and temperatures.