052/052B Class Destroyers

maozedong

maozedong

Banned Idiot
Re: DDG 052C Thread

kw64 said:
Just wondering, how come the phased array radars on PLAN ships have curved surface for the antenna cover, while most western warships the antenna cover is flat?
Click to expand...

052C最引人注目之处，就是艏楼四周加装了四具大型的固定式相控阵雷达天线，其上层结构呈八面体，往上朝内倾斜15度，而与中心轴线呈45度夹角的四个倾斜面各安装一具相控阵天线，安装方式与美制“阿利·伯克”级宙斯盾驱逐舰类似，有人亲切地戏称之为“板砖”。据称“板砖”的重要技术来源是乌克兰。中乌之间的合作早在1999年便已展开，而生产工作完全由大陆方面负责，俄罗斯工业界则称“板砖”为“海狮”相控阵雷达。“板砖”的天线外罩为弧形且明显向外突出，此为气冷系统的静压箱，而天线本身是平的。这四面“板砖”的面积约为 18.9平方米，比美国AN／SPY —1还大，采用波长较长的S波段操作，拥有较佳的远程侦测能力，实际侦测距离不详。但在安装方面，“板砖”的位置过低，受制于地球弧形表面，将使其平面搜索距离大减，此外，朝向后方的两块“板砖”位置没有特别加高，导致水平视线下缘被高起的尾楼结构挡到一些，影响到舰体后方的低空搜索。

They come from different types of products, 052C with air-cooled system, static pressure box, using curved surfaces, may be in order to be able to loose the heat from pressure box.

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crobato

crobato

Colonel
VIP Professional
Re: DDG 052C Thread

kw64 said:
Just wondering, how come the phased array radars on PLAN ships have curved surface for the antenna cover, while most western warships the antenna cover is flat?
Click to expand...

IMO, heat is being generated over the surface, and you need space in the radome to run cooling. Generally, heat tends to be produced behind the array in a PESA because that's where the emitter is located. This allows you to put a flat cover over the array. But if the emitters are right on the surface like with active elements, you cannot cool the array from behind, but run the cooling across the surface. This forces a curved cover.
 
duskylim

duskylim

Junior Member
VIP Professional
Re: DDG 052C Thread

Dear Sirs:

The whole series of pictures (from the website) is both illuminating and confusing.

In the 1st picture - of the land-based test installation, all of the ducting and piping is located BEHIND the array, running across the back from left to right of the red border.

Nonetheless there seems to be a rudimentary flat-planar plastic cover over the arrays' elements.

The 2nd and 3rd pictures are much more illuminating. They appear to show (respectively) an analysis of the heat distribution and of the air flow in the space behind the cover:

The 2nd picture shows the temperature distribution under the cover with cooling air coming from holes in the 4 corners of the array (which is confirmed in the last picture -number 6 - of the uncovered array).

The 3rd picture shows a 2-dimensional heat-and-airflow analysis of just one corner of the array. Its a little unsatisfactory as it does not show where the airflow finally exits, just where it enters and how it flows behind the cover and along the array's elements - my guess is that the cooling air is drawn inwards from tiny holes next to the elements themselves.

What confuses me is why resort to air-cooling in the first place? I am no expert on radars but I do have considerable knowledge of cooling (and various heat-exchange) systems. Air-cooling is quite limited compared to liquid cooling - that suggests an upper limit as the the power of those transmit-receive elements.
 
W

Wolverine

Banned Idiot
Re: DDG 052C Thread

Well there's absolutely no reason the array couldn't use both methods of cooling, air flow in the front and liquid in the back. In fact I would bet it does use both.
 
crobato

crobato

Colonel
VIP Professional
Re: DDG 052C Thread

duskylim said:
Dear Sirs:

The whole series of pictures (from the website) is both illuminating and confusing.

In the 1st picture - of the land-based test installation, all of the ducting and piping is located BEHIND the array, running across the back from left to right of the red border.

Nonetheless there seems to be a rudimentary flat-planar plastic cover over the arrays' elements.

The 2nd and 3rd pictures are much more illuminating. They appear to show (respectively) an analysis of the heat distribution and of the air flow in the space behind the cover:

The 2nd picture shows the temperature distribution under the cover with cooling air coming from holes in the 4 corners of the array (which is confirmed in the last picture -number 6 - of the uncovered array).

The 3rd picture shows a 2-dimensional heat-and-airflow analysis of just one corner of the array. Its a little unsatisfactory as it does not show where the airflow finally exits, just where it enters and how it flows behind the cover and along the array's elements - my guess is that the cooling air is drawn inwards from tiny holes next to the elements themselves.

What confuses me is why resort to air-cooling in the first place? I am no expert on radars but I do have considerable knowledge of cooling (and various heat-exchange) systems. Air-cooling is quite limited compared to liquid cooling - that suggests an upper limit as the the power of those transmit-receive elements.
Click to expand...

You're using either an AESA or a PESA with a TWT of extremely high power. The latter is actually more difficult to do so the former is more likely. AESAs are infamous for their heat generating qualities.

Yes, you need to cool from both in and out. My guess is the first picture was a prototype. Even powerful PESAs like the S300 radars are not spotted with this level of back end cooling. Adding cooling in the front would have been a later modification.
 
W

Wolverine

Banned Idiot
Re: DDG 052C Thread

duskylim said:
The 2nd picture shows the temperature distribution under the cover with cooling air coming from holes in the 4 corners of the array (which is confirmed in the last picture -number 6 - of the uncovered array).

The 3rd picture shows a 2-dimensional heat-and-airflow analysis of just one corner of the array. Its a little unsatisfactory as it does not show where the airflow finally exits, just where it enters and how it flows behind the cover and along the array's elements - my guess is that the cooling air is drawn inwards from tiny holes next to the elements themselves.
Click to expand...

If the cooling air is pumped into the enclosed space, why is there a photo of the array appearing to show that the four corners are the hottest areas on the array? Instead, maybe the cool air is pumped through the elements to the front of the array and the resulting hot air is sucked back in by those 4 corner vents. Just a thought.
 
Engineer

Engineer

Major
duskylim said:
What confuses me is why resort to air-cooling in the first place? I am no expert on radars but I do have considerable knowledge of cooling (and various heat-exchange) systems. Air-cooling is quite limited compared to liquid cooling - that suggests an upper limit as the the power of those transmit-receive elements.
Click to expand...

My guesses are as follow:
  • The plumbing required to cool the elements with liquid would probably be too sophisticated and far out weights the advantages brought by liquid-cooling.
  • The condensation caused by the cooling would be problematic. Condensation precipitating on the cold elements would be catastrophic.
  • Moisture can be extracted from the air before the air gets to the elements. Even if there is moisture, the condensation would only appear at the refrigeration unit, far away from the elements.

Wolverine said:
If the cooling air is pumped into the enclosed space, why is there a photo of the array appearing to show that the four corners are the hottest areas on the array? Instead, maybe the cool air is pumped through the elements to the front of the array and the resulting hot air is sucked back in by those 4 corner vents. Just a thought.
Click to expand...

The color could mean velocity or pressure gradient of the air.
 
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K

kroko

Senior Member
destroyer 052d?

Hi

I have seen in two websites, references to DDG 052D, an 7000-9000t air defence destroyer, which will be/is being built in dalian shipyard. I wonder if there is any truth to it?
 
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